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FIRST  AND   SECOND  ANNUAL  REPORT 


OF  PROGRESS   BY  THE 


STATE    GEOLOGIST 


AND     THE 


ASSISTANT  AND  CHEMIST 


V 

ON  THE  GEOLOGICAL  SURVEY  OP 


THK    ST^LTE    OF    IOWA. 


TOGETHER'  WI'SH  THE  fe^JBSTANCE   OP 


POPULAR     LETTERS 


CONTRIBUTED  TO  THE  NEWSPAPERS  OF    THE   STATE  DURING  THE    YEARS    1866 

AND   1867,    IN    ACCORDANCE    WITH  LAW;      ALSO    EXTRACTS    ORIGINALLY 

CONTRIBUTED    TO  SCIENTIFIC  JOURNALS     AS     A    PART    OP    THE 

WORK     OF     THE     SURVEY. 


DBS  MOINE8 : 

W.   PALMER,   STATE  PRINTER. 

1868. 


BOTH 

SCIENCES 

LIBRARY 


GEOLOGICAL  SURVEY. 


AN  ACT  providing  for  the  completion  of  the  Geological  Survey  of  the  State  of  Iowa.* 
SECTION  1.    Be  it  enacted  by  the  General  Assembly  of  the  State  of  Iowa,  That 
for  the  purpose  of  completing  the  Geological  Survey  of  the  State,  Charles  A. 
White,  of  Johnson  county,  is  hereby  appointed  State  Geologist,  and  shall  hold 
his  office  for  the  term  of  two  years,  or  until  his  successor  is  appointed. 

SEC.  2.  The  State  Geologist  shall  be  authorized  to  appoint  a  competent  assist- 
ant, and  also  a  skillful  analytical  and  experimental  Chemist,  who  shall  report  to 
the  State  Geologist  the  analysis  of  such  soils,  rocks,  coals,  ores  and  other  mineral 
substances,  as  he  may  submit  to  him  for  that  purpose.  He  shall  also  have  power 
to  employ  such  further  assistance  as  he  may  deem  necessary  to  prosecute  promptly 
and  efficiently  the  field-work  connected  with  the  survey.  All  persons  employed 
by  him  shall  be  under  his  direction,  and  subject  to  removal  by  him.  All  the 
specimens  of  minerals,  fossils,  rocks,  soils,  coals,  ores  or  other  geological  or  min- 
eral substances  of  any  value  or  interest  to  either  the  practical  or  amateur  geolo- 
gist, and  any  drawings  or  sketches  of  the  same  obtained  or  made  by  said  State 
Geologist,  as  well  as  the  copy -right  of  the  reports  and  all  books  printed  there- 
from, shall  belong  to  the  State,  and  no  specimen  copy,  draft,  or  part  of  the  same 
shall  be  given  away  or  sold,  or  permitted  to  be  carried  away  contrary  to  the  pro- 
visions of  this  Act ;  and  the  State  Geologist,  or  any  of  his  assistants  or  employes, 
or  any  other  person,  who  shall  violate  any  provision  of  this  section,  shall  be 
deemed  guilty  of  a  misdemeanor. 

SEC.  3.  It  shall  be  the  duty  of  the  State  Geologist  and  his  assistants  to  carry 
on,  with  as  much  expedition  as  practicable,  the  Geological  and  Mineralogical 
Survey  of  the  State,  including  observations  and  examinations  of  the  soil  for 
agricultural  purposes.  He  may  also  include  in  his  report  such  matters  as  per- 
tain to  physical  geography,  and  such  other  matters  as  properly  and  usually 
pertain  to  a  survey  of  this  kind  ;  it  being  expressly  required  of  the  State  Geologist 
and  his  assistants,  that  these  duties  be  performed  in  such  a  manner  as  to  give  to 
the  people  of  the  State  the  greatest  amount  of  practical  information  in  relation 
to  its  resources. 

SEC.  4.  it  shall  be  the  duty  of  the  State  Geologist,  on  or  before  the  first  Monday 
of  January  of  each  year,  to  prepare  a  report  of  said  survey  and  its  progress,  ac- 
companied by  such  maps  and  drawings  as  maybe  necessary  to  illustrate  the  same 
and  transmit  them  to  the  Governor,  who  shall  lay  a  copy  of  such  reports  before 

*  Extract  of  Chapter  73,  Laws  of  the  Eleventh  General  Assembly. 


4  REPORT  OF  STATE  GEOLOGIST. 

the  General  Assembly.  That  the  Geologist  shall,  as  far  as  practicable,  use  such 
words  in  his  reports  as  are  in  common  use,  and  that  he  shall  accompany  each 
volume  of  his  reports  with  a  glossary.  It  shall  also  be  his  duty  to  prepare,  from 
time  to  time  during  the  progress  of  the  survey,  communications  for  publication 
in  the  newspapers  of  the  State  (provided  it  shall  be  done  without  expense  to  the 
State),  embodying  such  information  in  reference  to  the  character  and  quality  of 
the  soil,  deposits  of  coal,  minerals  and  other  valuable  substances,  as  he  may  deem 
of  general  interest  and  importance  to  the  public. 

SEC.  5.  It  shall  be  the  duty  of  the  State  Geologist  to  cause  collections  to  be 
made  of  rocks,  soils,  fossils,  coals,  ores  ond  other  mineral  substances  discovered 
or  examined,  which  shall  b'e  disposed  of  as  follows,  to- wit :  All  rare  specimens, 
of  which  duplicates  can  not  be  found  and  all  specimens  from  which  descriptions 
or  illustrations  are  drawn  for  publication,  shall  be  deposited  in  the  cabinet  of  the 
State  University.  A  full  series  of  the  best  of  such  specimens  as  more  particularly 
exemplify  the  economic  geology  of  the  State,  shall  be  deposited  in  the  cabinet  of 
the  State  Agricultural  College.  All  other  specimens  shall  be  distributed  to  the 
cabinets  of  all  other  organized  institutions  of  learning  in  the  State,  giving  prefer- 
ence to  the  State  University,  the  State  Agricultural  College,  and  the  Medical 
College  at  Keokuk. 


FIRST  ANNUAL  REPORT 


OP 


CHARLES  A.  WHITE,  M.  D.,  STATE  GEOLOGIST. 


IOWA  CITY,  January  3,  1867. 
To  His  Excellency,  William  M.  Stone,  Governor  of  Iowa  : 

SIR:  In  accordance  with  section  four  of  chapter  seventy  -  three  of  the  laws 
of  the  Eleventh  General  Assembly,  I  herewith  submit  to  you  my  first  annual 
report  of  the  progress  of  the  Geological  Survey  of  the  State.  Upon  your  appro- 
val of  the  law  referred  to,  March  30th,  1866, 1  repaired  to  the  capital  for  the 
purpose  of  being  legally  qualified,  and  then  entered  immediately  upon  the  duties 
of  my  office.  I  appointed  Mr.  Chandler  Childs,  of  Dubuque,  as  my  field  -  assistant, 
and  Prof.  Gustavus  Hinrichs,  of  the  State  University,  as  chemist  of  the  survey. 
The  first  work  done  was  a  review  of  the  older  rocks  of  the  eastern  half  of  the 
State,  from  the  oldest  fossiliferous  formations  to  the  sub -carboniferous  limestones 
inclusive.  This  was  accomplished  by  visiting  various  localities  in  company  with 
my  field  assistant,  making  measurements  and  collecting  specimens  for  study,  and 
for  the  State  Cabinet. 

The  principal  object  of  this  review  was  that  we  might  obtain  as  complete  a 
knowledge  as  possible  of  the  full  series  of  the  formations  of  the  State,  in  their 
regular  order,  and  thus  enable  us  to  study  with  greater  precision  the  co£l- bearing 
strata,  to  which  it  is  proposed  to  devote  the  greater  part  of  each  season's  labor. 
After  accomplishing  this,  it  was  found  necessary  to  make  some  comparative 
examinations  of  the  coal  -  deposits  of  the  neighboring  States,  and  also  along  the 
northern  border  of  our  own  coal  -field.  Then  preparing  an  outfit  consisting  of  a 
pair  of  horses  with  a  covered  wagon,  tent  and  other  necessary  articles,  we  pro- 
ceeded to  the  southwestern  part  of  the  State  by  the  way  of  the  southern  tier  of 
counties,  and  subsequently  carried  on  careful  examinations  over  the  three  soutk- 
ern  tiers,  from  the  Missouri  River  to  those  counties  which  border  the  valley  of 
the  Des  Moines  River,  comprising  Decatur,  Ringgold,  Taylor,  Page,  Fremont, 
Mills,  Pottawattamie,  Cass,  Montgomery,  Adams,  Adair,  Union,  Madison,  and 
parts  of  Clarke,  Wayne  and  Appanoose  counties.  It  was  considered  of  great 
importance  that  we  should  know  the  extent  of  our  coal -field  in  that  direction,  as 
well  as  just  to  the  people  of  the  western  part  of  the  State,  because  the  examina- 
tions of  the  previous  survey  did  not  reach  them. 


Q  REPORT  OF  STATE  GEOLOGIST. 

Wishing  to  accomplish  all  that  was  possible  for  the  development  of  fuel  for 
our  State,  early  in  September  last  I  sent  my  assistant  to  the  counties  of  Franklin, 
Wright,  Cerro  Gordo,  Hancock,  Worth  and  Winnebago,  for  the  purpose  of  examin- 
ing that  region  for  deposits  of  peat,  while  I  continued  the  examinations  in  relation 
to  the  coal-field.  Peat  will  no  doubt  be  found  ia  large  quantities  in  other  parts 
ofj,he  State,  but  for  reasons  suggested  by  the  character  of  the  surface  in  relation 
to  the  streams  of  that  region,  climate,  &c.,  it  was  thought  to  be  one  of  the  most 
favorable  for  present  investigations  of  this  kind;  beside  which,  it  is  entirely 
beyond  the  limits  of  the  coal-field,  and  within  it  no  other  fuel  except  wood  may 
be  expected.'  -  •  ;  <• 

My  instructions  to  rriy'assistant  were  that  he  should  report  to  me  at  the  end  of 
every  w'efcU.'t&atl  faight'givje  t&3  results  to  the  people  through  the  public  press 
as  soan«a«  theywWe  ascertained /blit/I  regret  to  say  that  I  have  received  no  report 
from  him  for  more  than  three  months,  in  consequence  of  which  I  have  been 
obliged  remove  him,  and  have  appointed  Mr.  Orestes  H.  St.  John,  of  Waterloo, 
Black  Hawk  county,  in  his  stead.  I  continued  my  field-  work  until  the  lOih  of 
November  last,  at  which  time  the  weather  became  too  inclement  to  prosecute  it 
further  for  the  present  season. 

The  more  prominent  results  of  the  field  -  work  may  be  briefly  stated  as  follows : 
That  formation  known  among  geologists  as  the  coal  -  measures  consists  in  our 
State  of  a  succession  of  strata  of  sandstone,  limestone,  sandy,  clayey  and  car- 
bonaceous shales,  marls  and  coal;  and  is  divided  into  the  upper  and  lower 
series.  The  lower  series  only  is  found  along  eastward  and  northward  of  the  Des 
Moines  River  Valley,  and  consists  principally  of  shales  and  sandstone,  together 
with  the  coal.  Very  little  limestone  is  found  associated  with  them,  and  that  is 
always  more  or  less  impure.  This  series  contains  all  the  productive  coal-beds, 
and  consequently  furnishes  nearly  all  the  coal  now  obtained  in  the  State.  The 
upper  series  consists  principally  of  limestone,  with  some  fine-grained  sandstone 
and  marly  shale.  It  is  not  known  to  exist  at  all  northward  and  eastward  of  the 
Des  Moines  River,  but  to  the  southward  and  westward  of  that  river  it  reaches  a 
maximum  development  of  one  hundred  and  seventy  •  five  leet  in  thickness.  There 
are  at  least  two  carbonaceous  horizons  in  this  series,  one  of  which  embraces  the 
only  bed  of  coal  yet  found  in  the  western  part  of  the  State.  The  other  is. of 
limited  extent,  usually  showing  a  thin  seam  of  highly  carbonaceous  matter,  but 
in  the  form  of  shale,  and  entirely  worthless.  The  bed  of  coal  referred  to  finds 
its  greatest  development  along  the  valleys  of  the  Nodaways,  in  the  counties  of 
Adams,  Taylor  and  Page,  and  is  there,  at  most,  only  twenty  inches  in  thickness. 
Its  horizon  has  been  recognized  in  most  of  the  counties  referred  to,  but  the  coal- 
bed  is  found  to  diminish  in  thickness  to  the  eastward,  westward  and  southward, 
so  that  in  these  directions  little  is  seen  except  a  thin  band  of  carbonaceous  matter 
of  no  economic  value,  as  its  representative.  The  strata  of  this  series  are  nearly 
horizontal  in  an  easterly  and  westerly  direction,  so  that  one,  in  passing  from 
Madison  or  Clark  to  Fremont  or  Pottawatamie  counties,  would  be,  in  geological 
language,  constantly  upon  the  line  of  strike,  the  dip  of  all  the  strata  being  to  the 
southward,  and  nearly  coincident  with  the  fall  of  the  streams. 


REPORT  OF  STATE  GEOLOGIST.  7 

In  all  that  region  of  the  south-western  part  of  the  State,  comprising  the  thirteen 
or  fourteen  full  counties,  named,  the  only  accessible  rocks  are  those  of  the  upper 
coal  -  measure  series,  which  in  the  deeper  valleys  of  Madison  county  at  least,  I 
found  resting  upon  the  upper  part  of  the  lower  series,  as  at  present  understood; 
eastward  from  which  point,  the  upper  series  rapidly  disappears,  and  the  lower, 
with  its  coal,  becomes  accessible. 

This  determination  of  the  relative  position  of  the  strata  of  the  western  and 
central  parts  of  the  State,  which  was  first  made  known  by  my  labors  during  the 
past  season,  becomes  a  matter  of  very  great  economic  interest  to  the  people,  for 
upon  it  depends  the  direction  of  intelligent  effort  in  future  investigations  for  coal. 
It  is  known  that  the  upper  series,  in  the  region  referred  to,  contains  too  little  coal 
for  the  uses  of  the  inhabitants,  but  it  is  not  contrary  to  any  known  principles  of 
geology  to  expect  to  find  tlie  lower  series,  witJi  its  coal -beds,  extending  beneath  the  upper 
series  to  the  icestern  part  of  tlie  State,  by  sinking  shafts  of  not  impracticable  depth  down 
to  them. 

During  the  progress  of  the  field-work,  I  wrote  frequent  articles  for  the  public 
press,  explanatory  of  its  results,  in  accordance  with  the  law.  I  herewith  transmit 
to  you  printed  copies  of  the  same,  thirty- three  in  number,  as  apart  of  my  report. 

The  desire  on  the  part  of  the  principal  newspapers  of  the  State  to  obtain  these 
communications  has  been  so  great  that  I  have  prepared  from  two  to  four  manu- 
script copies  of  each  one  of  them,  and  sent  them  simultaneously  to  as  many  news- 
paper offices  for  publication.  These  have  again  been  copied  into  other  papers  of 
the  State ;  in  addition  to  which  the  leading  newspapers  of  the  neighboring  States 
have  frequently  made  copious  extracts  therefrom. 

A  large  quantity  of  material  has  been  collected,  consisting  of  minerals,  fossils, 
soils,  clays,  fuels,  samples  of  building- rocks,  mineral  waters,  &c.,  &c.  I  have  not 
yet  had  time  to  fully  investigate  and  arrange  these  collections,  but  they  are  known 
not  only  to  comprise  much  that  the  State  Cabinet  has  never  before  contained,  but 
also  a  number  of  species  not  before  found  in  the  West,  some  of  which  are  yet  new 
to  science.  My  first  care  will  be  to  label  and  arrange  these  collections  in  such  a 
manner  that  a  knowledge  of  their  ownership,  geological  position  and  location  can 
not  be  lost.  Those  of  which  it  is  desirable  to  have  chemical  analyses  and  investi- 
gations made,  are  in  the  hands  of  the  chemist.  By  reference  to  his  report,  here- 
with annexed,  it  will  be  seen  that  he  has  entered  upon  his  work  with  an  earnest- 
ness  and  care  which  give  promise  of  the  most  satisfactory  results.  It  is  proposed 
to  devote  a  considerable  part  of  the  time  during  the  winter  months  to  the  critical 
investigation  of  these  collections,  and  whenever  it  may  be  necessary  to  secure  to 
the  State  the  credit  of  priority  in  those  labors,  the  results  will  be  published  in 
some  of  the  scientific  periodicals  of  the  country  in  advance  of  my  final  report. 
After  this  has  been  done,  the  specimens  will  be  distributed  according  to  law. 

The  Faculty  of  the  State  University  have  generously  given  me  the  free  and 
exclusive  use  of  their  large  cabinet  room  for  an  office,  and  in  which  to  study  and 
arrange  the  collections.  The  railroad-companies  of  the  State  give  me  free  access 
to  the  records  of  their  surveys,  and  offer  me  all  facilities  for  investigation  that  can 


g  REPORT  OF  STATE  GEOLOGIST. 

be  desired.  I  find  the  people  much  interested  in  the  progress  of  the  work,  and 
everywhere  kind  and  obliging.  As  soon  as  the  weather  will  admit  of  field 
operations  in  the  Spring,  it  is  proposed  to  take  up  that  work  where  it  was  left  at 
the  close  of  the  season  just  passed,  giving  especial  attention  to  the  subjects  of 
coal  and  peat. 

All  of  which  is  respectfully  submitted. 

CHARLES  A.  WHITE, 

State  Geologist. 


REPORT  OF  THE  CHEMIST. 


To  DR.  C.  A.  WHITE,  State  Geologist  : 

SIR  :  I  herewith  submit  the  following  as  a  report  of  progress  of  the  chemical 
investigations  connected  with  the  survey :  Up  to  date,  two  hundred  and  thirty  - 
two  numbers  of  specimens  have  been  received  at  the  laboratory  for  examination; 
many  of  these  numbers  representing  duplicates.  The  material  thus  accumulated 
by  you  during  the  first  season  of  the  survey,  is  not  only  large  in  amount,  but  also 
of  great  intrinsic  value  for  the  scientific  and  economic  mineralogy  of  the  State. 
The  specimens  have  all  been  labeled  by  numbers,  which  numbers  are  here  used 
to  designate  them. 

I.  MINERAL  WATERS 

Have  been  received  from  Mt.  Pleasant  (114),  Ottumwa  (121),  Bloomfield  (24),  and 
near  Salt  Creek,  Davis  county,  (72);  also,  water  and  its  peculiar  sediment  from 
the  Missouri  Eiver  (187.)  Of  these,  the  first  four  have  been  analyzed.  These 
analyses,  together  with  one  of  a  spring  water  made  for  the  Iowa  Hospital  for  the 
Insane,  constitute  the  only  analyses  yet  made  of  the  waters  of  the  State. 

II.  ROCKS  AND   SOILS. 

A  considerable  number  have  been  received.  No.  8  from  Burlington,  Nos.  77 
and  78  from  Madison  county,  and  No.  79  from  Adair  county,  have  been  examined; 
No.  10  from  Clarke's  quarry,  near  Iowa  City,  has  been  analyzed,  and  found  to  owe 
its  dark  color  to  phosphate  of  protoxide  of  iron.  As  phosphates  are  especially 
fertilizing,  it  will  be  important  to  investigate  other  rocks  in  the  same  direction. 
Of  soils,  none  have  been  as  yet  analyzed;  such  analysis  can  be  more  expeditiously 
and  accurately  made  when  a  larger  number  of  samples  shall  have  been  collected. 

III.  COAL  AND  PEAT. 

The  analyses  of  coals  made  by  Prof.  Whitney,  the  former  State  Chemist,  have 
been  discussed.  These  analyses  plainly  show,  that  the  combustible  part  in  the 
Iowa  coals  is  very  nearly  uniform,  consisting  of  forty -five  per  cent  of  bitumen 
and  fifty  -  five  per  cent  of  fixed  carbon ;  the  great  variation  observed  in  the 
difierent  coals  analyzed  being  due  to  the  varying  proportions  of  ashes  and 
moisture  associated  with  the  combustible  part.  The  theoretical  bearing  of  these 
results  upon  the  formation  of  coal  is  apparent.  Their  practical  importance  is 
also  very  plain,  for  a  determination  of  the  amount  of  ashes  of  the  dried  coal  is 
2 


JQ  REPORT  OF  STATE  GEOLOGIST. 

equivalent  to  the  more  elaborate  analysis.  It  will  be  important  to  make  many 
further  analyses,  in  order  to  ascertain  whether  the  same  law  will  hold  good  for 
all  Iowa  coals. 

Of  new  analyses,  the  following  have  been  made:  (124)  cannel  coal  from  Mt. 
Pleasant,  Henry  county;  (136)  coal  from  Bentonsport,  Van  Buren  county ;  (123) 
peat  from  Solon,  Johnson  County;  (125)  peat  from  Mason  City,  Cerro  Gordo 
county;  (126)  the  same  condensed. 

IV.      MINERALS. 

Celestine.  The  specimens  brought  by  you  from  Fort  Dodge  proved  to  be  sul- 
phate of  Strontia  or  Celestine,  which  according  to  Whitney  has  not  before  been 
recognized  in  any  locality  west  of  Ohio. —  Wisconsin  Rep&rtt  page  113. 

Gypsum.  Nos.  9,  29  and  35,  from  Dubuque;  No.  23  from  Fort  Dodge;  the 
latter  white,  and  almost  chemically  pure. 

Barytes  or  Heavy  Spar.  Nos.  4  and  5,  from  Bremer  county ;  No.  7,  from  Decatur 
county;  Nos.  40,  42,  and  others,  from  Dubuque. 

Epsbmite  or  Sulphate  of  Magnesia.  (Nos.  167  and  168)  discovered  by  you  some 
years  ago  near  Burlington. 

Calc  spar  in  many  varieties,  as  No.  16.  Dog-tooth  spar :  geodes  from  Waverly, 
Bremer  county;  No.  17,  the  same  with  Brown  spar  covering;  Nos.  33  and  48, 
Spars,  and  other  varieties  from  Dubuque;  Nos.  2  and  3,  Anthraco-nite  in  fine 
columnar  masses  from  Waverly,  Bremer  county.  Nos.  60  and  other,  Rock  Milk, 
from  Dubuque;  177,  Dog-tooth  spar,  from  Iowa  Falls. 

Manganese,  has  been  found  in  dendrites  on  slabs  from  Anampsa,  (Nos.  13  and 
14)  on  calcareous  spars  from  Waverly,  (No.  17)  and  Iowa  Falls,  (177.)  It  has  also 
been  delected  as  Wad  (60,  61,  67)  and  Pyrolusite  (47)  from  Dubuque. 

Zinc,  lead,  and  iron  ores  have  been  received  and  determined,  but  not  yet 
analyzed. 

The  fine  collection  of  geodes  from  Bentonsport  has  been  partially  investigated. 
The  full  investigation  of  this  mineralogical  treasure  will  require  much  further 
labor. 

The  specimen  No.  121  from  Red  Rock,  Marion  county,  will  probably  prove  to 
be  a  new  mineral  species. 

A  full  analysis  has  been  made  of  clay  from  Iowa  Falls;  No,  20  is  a  remarkably 
pure  marly  clay;  No.  21,  a  fire  clay  containing  some  ferruginous  sand,  and  well 
adapted  to  various  kinds  of  fine  pottery. 

From  the  work  already  done,  both  in  regard  to  the  material  collected  in  the 
field,  and  the  study  in  the  laboratory,  I  may  venture  to  predict  that  your  final 
report  will  contain  a  chapter  on  the  scientific  and  economic  mineralogy  of  Iowa, 
consisting  of  the  results  of  investigations,  hitherto  only  barely  commenced. 

GUSTAVUS  HINRICHS, 
Chemut. 


POPULAR  LETTERS 


OF 


THE  STATE  GEOLOGIST 


FOR    1866. 


INTRODUCTORY 


By  reference  to  the  law  of  the  Eleventh  General  Assembly,  on  the  opening 
page,  it  will  be  seen  that  provision  wa«  made  for  the  publication  of  newspaper 
reports  of  the  observations  made  during  the  progress  of  the  State  Geological 
Survey. 

This  provision,  although  a  novel  feature  of  law  relatingj;o  geological  surveys, 
and  adding  largely  to  the  labors  of  those  in  charge,  has  nevertheless  become 
very  popular  with  the  people  of  Iowa  during  the  last  two  years,  and  it  is  believed 
also  that  they  have  been  much  benefitted  by  its  fulfillment.  Instead  of  making 
records  of  observations  to  be  filed  away  in  the  office  until  a  future  General 
Assembly  should  provide  for  their  publication,  and  when,  through  lapse  of 
time,  many  opportunities  to  take  practical  advantage  of  such  information 
would  have  been  lost  to  our  citizens,  these  results  have  been  made  immedi- 
ately available  to  all  by  the  frequent  publication  of  letters  from  the  field  and 
from  the  office,  in  the  various  State  newspapers. 

These  letters  were  almost  always  written  in  "  manifold,"  and  one  copy  inva- 
riably sent  to  the  newspaper  of  the  neighborhood  where  the  observations  recorded 
were  made ;  and  the  others,  from  two  to  ten  in  number,  were  sent  simultaneously 
to  other  papers  in  various  parts  of  the  State,  amounting  m  all  to  between  forty- 
five  and  fifty,  in  all  of  which  they  have  appeared  as  original  matter. 

Many  of  those  letters  wBre  written  by  the  light  of  the  camp-  lantern,  after  the 
field  -  labors  of  the  day  were  over,  and  were  consequently  unsatisfactory  to  the 
writer,  because  it  was  inevitable  that  minor  errors  should  be  admitted  into  com- 
munications made  before  the  observations  were  complete.  Again,  many  of  them 
having  been  written  for  different  readers,  while  the  subjects  of  each  were  similar, 
it  was  often  necessary  to  repeat  in  one  what  had  already  been  written  in  another ; 
for  it  was  the  aim  of  the  writer  to  present  the  information  contained  in  those 
letters  in  such  a  form  as  to  be  readily  understood  by  all,  and  also  to  present  such 
other  matter  as  should  be  attractive  to  the  general  readers,  and  thus  awaken 
popoular  interest  in  geological  subjects. 

By  request  of  the  Committee  of  the  Senate  who  ordered  the  printing,  such 
errors  and  repetitions  have,  to  a  great  extent  at  least,  been  excluded,  so  that 
what  is  said  of  many  of  the  counties  appears  somewhat  changed  from  the  form 
in  which  it  originally  appeared  in  the  newspapers.  An  exception  to  the  rule  of 
excluding  repetitions  is  made  in  favor  of  whatj  has  been  said  in  rclsiiinn  to  the 
growth  of  forest  trees.  This  is  a  matter  of  so  much  importance  that  loo  much 


-£4.  REPORT  OF  STATE  GEOLOGIST. 

can  not  be  said  to  encourage  the  people  to  plant  largely  of  all  kinds  of  our  native 
trees,  which  it  is  now  known  will  grow  as  thriftily  upon  prairie  soil  as  any  where 
else.  It  is  to  be  regretted  that  time  would  not  allow  the  arrangement  of  the  mat- 
ter contained  in  those  letters  according  to  the  various  subjects  discussed.  Instead 
of  this,  the  subject  matter  is  left  in  the  order  of  time  in  which  the  observations 
were  made,  or  according  with  the  progress  of  the  work. 

The  scientific  reader  will  thus  understand  why  it  is  that  official  reports  of  the 
survey  are  presented  in  this  unusual  form,  but  he  must  not  for  a  moment  suppose 
that  any  scientific  principle  will  be  sacrificed  to  popular  prejudice  or  preference. 
All  matters  that  are  more  abstractly  scientific  in  their  character  are  receiving 
their  full  share  of  attention  as  the  work  progresses,  and  several  papers  of  this 
character  have  already  been  published  in  various  scientific  journals,  two  of  which 
are  herein  re-  printed.  It  is  of  course  expected  that  a  comprehensive  final  report 
will  be  published  in  standard  form,  in  addition  to^these  preliminary  papers  and 
reports. 

Considering  the  fact  that  only  a  few  years  ago  geology  was  not  made  a  part  of 
even  a  liberal  education,  it  is  thought  advisable  to  give  a  few  words  of  popular 
explanation  of  its  principles  so  far  as  relates  to  the  geological  structure  of  our 
State.  All  the  rock  formations  of  Iowa  are  stratified  ;  that  is,  they  have  without 
doubt  been  formed  at  the  bottom  of  the  sea  in  more  or  less  regular  layers,  and 
now,  since  their  elevation  from  the  sea,  they  extend,  as  it  were,  in  broad  sheets, 
lying  the  one  above  the  other,  beneath  the  whole  surface. 

In  Iowa  the  order  of  superposition  of  the  formations  is  comparatively  simple, 
because  no  great  disturbance  of  the  strata  has  taken  place  here,  as  has  been  the 
case  in  some  other  regions.  The  characters  and  com  position  of  our  rocks  are 
various,  being  limestone,  sandstone,  inagnesiau  lincu'S'one,  shale,  clay,  coal,  &c., 
for  whether  hard  or  soft,  geologists  call  them  all  rocks.  Even  the  coal,  since  it 
lies  in  beds  parallel  with  beds  of  rock,  is  practically  itself  a  stratified  rock, 
whether  the  theory  of  its  marine  origin  advocated  by  the  chemist  in  his  letters  is 
the  correct  one,  or  not. 

Nearly  all  stratified  rocks  are  found  to  contain  fossil  remains,  which  in  ours  are 
principally  shells  and  corals  of  many  kinds;  and  by  the  study  of  these,  geologists 
find  that  certain  sets  of  strata  are  characterized  by  certain  fossils  that  are  found  in 
them,  and  nowhere  else.  It  is  this  which  gives  collections  of  fossils  their  great 
value,  for  without  the  information  they  thus  afford  they  would  be  of  no  more 
value  than  broken  crockery.  By  studying  the  fossils  of  all  the  formations  we  are 
able  to  determine  the  relative  position  of  any  one  of  them,  even  if  but  a  small 
part  of  a  single  one  is  found  exposed;  for  this  relation,  when  onca  ascertained,  is 
found  in  all  cases  to  be  constant  and  reliable.  The  strata  thus  studied  are  divided 
into  contiguous  groups  and  variously  named  in  an  order  indicative  of  their  rela- 
tive ages,  as  Lower  Silurian,  Upper  Silurian,  Devonian,  Carboniferous,  &c.;  the 
lowest  in  the  series  being  the  oldest,  and  the  others  successively  of  later  and  later 
origin.  The  strata  of  our  State  do  not  now  lie  in  a  perfectly  horizontal  position. 
If  they  did  we  could  find  little  more  than  the  upper  ones,  but  by  a  change  in  the 


REPORT  OF  STATE  GEOLOGIST.  15 

surface  which  probably  went,  on  slowly  while  they  were  being  deposited,  they 
have  been  elevated  so  that  their  slightly  upturned  edges  come  to  the  surface  as 
one  goes  from  the  southwest  to  the  northeastern  corner  of  the  State,  where  the 
oldest,  and  geologically  the  lowest  are  found.  It  will  thus  be  seen  that  the  plane 
of  any  of  the  geological  formations  beneath  the  surfice  have  no  necessary  relation 
to  the  plane  of  that  general  surface.  For  instance,  of  the  rocks  exposed  along 
the  Mississippi  river,  those  in  Alamakee  and  Clayton  counties  are  the  lowest 
geologically,  although  topographically  the  highest,  and  as  one  goes  down  the  Mis- 
sissippi, he  goes  up  in  the  geological  scale. 

Through  the  politeness  of  Dr.  Mark  Ranney,  Superintendent  of  the  State  Hos- 
pital for  the  Insane  at  Mount  Pleasant,  Henry  county,  who  presented  a  series  of 
carefully  preserved  specimens  of  the  borings  of  their  Artesian  well,  we  obtained 
very  satisfactory  proof  of  this  order  of  superposition  of  the  strata. 

An  examination  of  these,  enabled  us  to  identify,  by  their  litbological  characters, 
the  formations  which  the  drill  passed  through,  because  we  were  previously 
acquainted  with  those  characters,  having  studied  the  same  rocks  as  they  success- 
ively make  their  appearance  at  the  surface  northward. 

At  the  depth  of  1125  feet,  the  bottom  of  the  boring,  we  identified  the  rock  as 
the  same  as  that  which  f  >rms  the  tops  of  the  hills  at  Dubuque,  more  than  a 
hundred  miles  northward;  and  if  the  boring  had  been  continued,  the  drill  would 
have  reached  those  rocks  which  come  to  the  surface  still  further  to  the  northward. 
The  record  of  that  boring  says  that  the  drill  passed  through  no  coal.  This  could 
have  been  predicted,  because  the  first  rocks  pierced  by  the  drill  were  those  of  the 
sub-carboniferous  limestone  which  is  found  to  form  the  floor,  so  to  ppeak,  of  the 
formation  which  contains  the  coal.  If  they  had  commenced  this  boring  in 
Jefferson,  the  next  county  westward,  they  would  doubtless  have  passed  through 
at  least  a  portion  of  the  coal-measure  strata  before  reaching  the  limestone  upon 
which  they  started  at  Mt.  Pleasant.  If  they  had  commenced  their  boring  in  the 
southwestern  part  of  the  State  they  would  have  been  obliged  to  pierco  many 
hundred  feet  of  barren  and  probably  also  productive  coal-measure  strata  before 
their  drill  reached  the  limestone  which  is  at  the  surface  in  Henry  county  where 
they  began  to  bore.  From  what  has  been  said  it  will  be  seen  that  the  general  dip 
of  all  the  formations  is  to  the  southward,  although  it  is  so  slight  that  is  not 
perceptible  to  the  eye  ;  so  that  the  oldest  formation  is  in  the  northeast  corner  of 
the  State,  and  the  newest  in  the  southwest  corner.  This  is  true  with  one  excep- 
tion. A  formation  newer  than  all  the  otheis.  the  Cretaceous,  is  known  to  occupy 
a  large  area  in  the  northwestern  part  of  the  State,  where  a  large  part  at  least,  of 
the  other  formations  dip  beneath  it  to  the  northwestward. 

We  have  evidence  which  is  admitted  by  all  as  conclusive,  that  after  all  the 
stratified  rocks  had  been  formed,  there  was  a  time  when  the  whole  northern 
hemisphere,  as  far  south  at  least,  as  the  Ohio  river  in  our  country,  was  covered 
with  ice,  as  Northern  Greenland  is  at  the  present  time.  The  ice  is  believed  to 
have  existed  as  an  almost  continuous  glacier,  moving  with  an  infinitely  slow  but 
constant  motion  to  the  southward,  grinding  up  in  its  passage  the  surface  portions 


^g  REPORT  OF  STATE  GEOLOGIST. 

of  the  formations  upon  which  it  rested  into  the  fine  material  that  now  constitutes 
our  soil  and  subsoil,  and  which  now  covers  those  formations  like  a  mantle,  so  that 
we  seldom  see  them  in  place  except  when  they  have  been  bared  by  the  streams 
while  they  were  cutting  out  their  own  valleys.  The  granite  boulders  and 
pebbles  so  common  in  all  parts  of  the  State  were  brought  down  from  the  north 
by  the  same  means,  for  we  have  no  other  granitic  rocks  within  our  borders,  and 
these  with  the  material  ground  up  by  ths  glaciers  were  mixed  into  a  heterogenous 
mass  which  now  occupies  the  surface  every  where,  and  is  called  "drift"  by 
geologists.  Lumps  of  copper,  doubtless  from  the  Lake  Superior  region,  and 
masses  of  lead  ore  probably  from  the  Dubuque  lead  region  are  sometimes  found 
in  the  drift  of  the  different  parts  of  the  State,  where  they  happened  to  be  released 
by  the  melting  ice  as  the  glacial  epoch  passed  away.  In  Northern  Iowa  also, 
quite  beyond  the  limits  of  our  coal-field,  lumps  of  coal  have  been  found  in  the 
drift  which  the  inhabitants  sometimes  regard  as  an  indication  of  the  existence  in 
their  neighborhood  of  a  bed  of  coal.  But  these  lumps  were  probably  brought 
down  by  the  ice  from  a  thin  bed  of  coal  which  is  believed  to  exist  in  Southern 
Minnesota,  and  which  belongs  to  rocks  of  Cretaceous  age,  and  consequently 
having  no  connection  with  the  Iowa  coal-field.  The  subject  of  the  drift  forma- 
tion will  be  found  further  discussed  in  the  folio  wing"  pages  under  the  heads  of 
"Drift  phenomena  in  Southern  Iowa,"  and  "  Lakes  of  Iowa,  past  and  present." 

The  term  "  coal-measures"  is  one  introduced  from  England,  and  simply  means 
the  formation  which  contains  the  coal.  It  was  once  believed  that  all  the  coal  of 
the  earth  is  contained  in  the  formation  of  that  particular  geological  age,  but  sab- 
sequent  investigation  has  proved  this  view  to  have  been  incorrect.  We  have 
now  much  evidence  tending  to  prove  that  all  the  coal  yet  found  in  the  far  West, 
as  we  in  Iowa  understand  those  wcrds,  is  of  much  later  origin  than  our  own, 
and  with  which  ours  has  no  connection  by  continuity  of  formations. 

The  coal-measures  of  Iowa  ai  e  properly  separable  into  upper,  middle  and  lower 
divisions.  The  first  lies  wholly  to  the  southward  and  westward  of  the  Des  Moines 
River,  occupying  the  surface  in  the  southwestern  part  of.  the  State  over  an  area 
equal  in  extent  to  that  of  the  State  of  Vermont.  The  second  doubtless  underlies 
the  whole  of  the  first,  but  it  occupies  the  surface  only  aloi>g  its  northern  and  east- 
ern borders,  including  the  greater  part  of  the  region  of  the  Raccoon  Rivers,  which 
region  is  more  particularly  referred  to  in  Mr.  St.  John's  report,  on  another  page. 
The  lower  coal-measures  occupy  the  surface  of  a  large  area,  averaging  some  fifty 
miles  in  width,  and  about  one  hundred  and  seventy- five  miles  in  length,  through 
the  middle  of  which  the  Des  Moines  River  runs  longitudinally  in  a  southeasterly 
direction,  from  a  little  above  Ft.  Dodge,  nearly  to  Keokuk.  Over  nearly  the 
whole  of  this  large  surface  coal  may  reasonably  be  sought  for.  To  the  northward 
and  eastward  of  it,  it  is  useless  to  look  for  coal  except  in  small  "  patches"  or  out- 
liers. These  are  almost  always  unproductive  of  a  workable  bed  of  coal ;  the 
large  outlier  extending  from  Muscatine  nearly  to  Davenport  being  an  exception. 
To  the  southward  and  westward  of  this  region  it  is  believed  that  coal  will  be 
found  by  sinking  shafts  to  a  greater  or  less  depth. 

The  lower  coal-measures  contain  all  the  heaviest  beds  of  coal,  and  by  far  the 


REPORT  OF  STATE  GEOLOGIST.  17 

largest  part  to  be  found  in  the  State.  The  middle  measures  contain  some  worka- 
ble beds,  but  the  upper  series  are  believed  to  contain  only  one  bed  of  coal,  the 
greatest  thickness  of  which  is  only  twenty  inches. 

The  lower  coal  measures  are  made  up  principally  of  sandstone,  shales,  clay  and 
coal,  with  very  little  limestone ;  the  middle,  of  similar  materials,  but  has  more 
limestone,  less  sandstone,  and  less  coal,  while  the  upper  coal  -  measures  are  com- 
posed largely  of  limes' one,  which  in  Madison  county  alone  is  found  to  reach  a 
thickness  of  more  than  a  hundred  feet,  beside  the  other  strata  exposed  there. 

The  lower  coal-measures  disappear  beneath  the  middle  and  upper  measures  to 
the  southward  and  westward,  but  we  may  confidently  expect  to  reach  the  con- 
tinuation of  those  strata  by  sinking  deep  shafts  in  the  western  part  of  the  State. 
It  is  not  absolutely  certain  that  coal  will  be  found  in  those  strata  when  they  are 
so  reached,  but  when  a  similar  condition  of  the  strata  are  found  to  exist  in 
densely  populated  countries,  capitalists  do  not  hesitate  to  invest  their  money  in 
such  enterprises,  and  the  lime  will  doubtless  come  when  it  will  be  done  in  Western 
Iowa. 

However,  since  coal-beds  are  liable  to  thin  out  as  the  distance  increases  from  any 
given  maximum  point  of  development,  and  that  all  formations  are  expected  to  be 
thinnest  at  their  borders,  it  will  be  less  hazardous  as  well  as  less  expensive  to 
commence  such  enterprises  in  the  valleys  near  the  eastern  or  northern  border  of 
the  upper  or  unproductive  coal-measures,  say  in  the  counties  of  Decatur,  Clarke, 
Madison  and  Adair;  and  if  successful  at  those  points  it  would  encourage  similar 
enterprises  still  farther  and  farther  to  the  westward.  Yet  we  do  not  know  that 
the  maximum  development  of  the  coal  beds  may  not  be  to  the  westward  of  the 
Des  JMoines  river  region. 

People  throughout  the  State  very  often  ask  the  following  questions  by  letter 
and  otherwise  :  What  relative  position  does  coal  hold  to  limestone,  sandstone  or 
other  strata?  What  is  regarded  as  "coal  -  blossom,"  erasure  indication  of  the 
presence  of  coal  beneath  the  surface?  The  term  "coal-blossom"  is  not  used  by 
geologists,  but  those  who  use  it  appear  to  mean  the  presence  of  per  oxide  of  iron, 
or  simple  iron-rust  in  the  water  of  springy  places,  and  impregnating  the  earth 
around  where  it  issues.  So  far  as  that  appearance  is  concerned  it  amounts  only 
to  this  :  The  strata  associated  with  the  coal,  and  also  the  coal  itself,  almost 
invariably  contain  more  or  less  iron,  which  being  oxidized  passes  out  with  the 
water  which  finds  its  way  over  or  through  them.  But  while  this  is  true,  other 
strata  which  have  no  possible  connection  with  coal,  also  at  times  are  found  to 
contain  iron  in  a  similar  form,  which  of  course  presents  similar  appearances  at 
the  surface. 

As  to  the  relative  position  of  c  >al-beds  with  other  strata,  the  rule  is  that  a  bed 
of  clay,  commonly  called  fire  -  clay,  underlies  a  bed  of  coal,  while  a  bed  of  shale, 
often  called  soapstone  by  the  people,  almost  always  overlies  it.  Sometimes,  how- 
ever, sandstone,  or  even  limestone,  has  been  found  to  rest  upon,  or  to  underlie,  a 
bed  of  coal. 

In  the  following  pages,  a  limestone  will  be  referred  to  which  underlies  all  the 
3 


lg  REPORT  OF  STATE  GEOLOGIST. 

coal-measure  strata,  and  beneath  which  it  is  useless  to  search  for  coal.  This  is 
the  sub-carboniferous  limestone,  and  is  usually  found  to  belong  to  that  division 
which  geologists  have  named  the  St.  Louis  limestone,  because  the  same  formation 
is  well  exposed  near  that  city.  It  is  by  no  means  meant  that  limestone  is  never 
found  above  the  coal,  for  the  upper  coal-  measures  are  largely  composed  of  lime- 
stone, and  the  general  appearance  of  the  rock  of  these  two  limestone  formations 
is  often  almost  identical,  yet  when  one  is  acquainted  with  the  fossils  which  char- 
acterize e;tch,  he  will  know  without  hesitation  whether  a  given  exposure  belongs 
above  or  below  the  productive  coal-measures.  Since  the  lower  coal-measures 
contain  almost  no  limestone,  any  such  rock  tound  in  the  region  occupied  by  that 
formation,  as  for  instance  along  the  Des  Moines  River,  may  almost  certainly  be 
referred  to  the  sub  -  carboniferous  formation  ;  because  the  streams,  in  cutting  out 
their  own  valleys,  have  bared  the  limestone  after  they  had  cut  clear  through  the 
coal -measure  strata.  From  the  fact  that  this  limestone  is  so  often  exposed  near 
the  streams  which  run  through  the  region  occupied  by  the  lower  coal  -  measures, 
it  is  evident  that  no  very  deep  mining  will  be  requisite  in  that  region,  to  reach  all 
the  coal  that  exists  there,  because  all  the  coal  lying  above  the  limestone  will 
usually  be  obtained  by  drifting  into  the  edges  of  the  beds  which  crop  out  at  the 
sides  of  the  valleys.  Strictly  speaking,  there  are  no  indications  that  absolutely 
prove  the  presence  of  coal  beneath  any  given  spot,  but  since  coal-beds  are  known 
to  have  very  considerable  extent  beneath  the  surface,  and  to  lie  in  nearly  a  uni- 
form plane,  one  may  often  make  very  satisfactory  calculations  as  to  its  presence 
or  absence.  Thus,  if  a  bed  of  coal  is  found  cropping  out  in  one  side  of  a  valley, 
one  may  expect  to  find  the  same  bed  cropping  out  of  the  other  side  of  it ;  and  if 
a  similar  exposure  should  be  found  in  another  valley  a  few  miles  distant,  it  is 
reasonable  to  suppose,  in  our  coal-field  at  least,  that  the  two  exposures  are  parts 
of  the  same  bed,  and  that  it  is  continuous  beneath  the  whole  intermediate  space, 
and  further,  that  it  may  be  reached  at  an  estimated  depth  by  sinking  a  shaft  down 
to  it  from  the  high  land  between  the  two  valleys.  Beside  this,  it  will  be  seen 
from  what  has  been  said  that  the  geologist  is  able  to  draw  a  line,  at  least  approxi- 
mately, and  say  "  beyond  this  line  it  is  useless  to  explore  for  coal,  while  within  it 
there  is  a  reasonable  prospect  of  finding  coal." 

Mining  in  our  State  will  always  be  mainly  confined  to  coal,  as  will  be  seen  by 
reference  to  descriptions  of  the  extent  and  character  of  the  coal-field  on  the  follow- 
ing pages.  Next  in  importance  comes  the  lead  mines  of  Dubuque,  which  although 
very  important,  occupy  a  very  limited  area.  The  present  prospect  that  other 
mineral  substances  will  be  found  in  paying  quantities  is  not  encouraging.  Occa- 
sional masses  and  small  deposits  of  iron  ore  are  often  found,  but  none  have  yet 
been  discovered  that  will  warrant  the  erection  of  a  furnace,  and  even  if  it  were 
so,  as  soon  as  our  northern  and  southern  railroads  are  built,  iron  from  the  Iron 
Mountain  region  in  Missouri  would  doubtless  be  brought  here  more  cheaply  than 
we  could  manufacture  it  from  our  own  scanty  ores. 

AUTHORSHIP. 

The  articles  on  "Surface  Geology  of  the  Middle  Region  of  Western  Iowa,' 


REPORT  OF  STATE  GEOLOGIST.  19 

"  The  Geology  of  the  Raccoon  River  Region,"  and  the  report  which  bears  his 
name,  are  the  work  of  the  Assistant.  The  articles  on  "The  Fuel  of  Iowa," 
"Waters  of  Iowa,"  "Rocks  of  Iowa,"  "  Valuation,  composition,  and  proximate 
analysis  of  coals,"  "  Mineralogy  of  Iowa,"  together  with  the  reports  which  bear 
his  name  are  the  work  of  the  Chemist.  All  the  remaining  matter  is  by  the  State 
Geologist.  As  usual  in  such  cases,  each  author  is  to  be  considered  as  responsible 
for  his  own  work. 


SURVEY  OF  COUNTIES. 


BLACK  HAWK  AND   BREMER  COUNTIES. 

HYDRAULIC    CEMENT. 

In  April  of  1866,  while  making  the  examinations  referred  to  in 
the  preceding  report,  a  communication  was  sent  to  the  Waterloo 
Courier,  which  contained  the  following  paragraphs  : 

"Throughout  the  northeastern  portion  of  the  State,  the  pre- 
vailing character  of  nearly  all  the  formations  is  magnesian  lime- 
stone, which  character  extends  to  the  Devonian  rocks  of  your 
county,  although  the  same  formation  in  Johnson  county,  and  else- 
where in  the  State,  is  but  very  slightly  magnesian.  It  is  a  well 
known  fact  that  rocks  quite  various  in  their  chemical  composition 
will  nevertheless  make,  when  properly  prepared,  excellent  hydraulic 
cement,  and  among  the  rocks  from  which  this  cement  is  prepared 
are  the  very  kinds  of  magnesian  limestones  which  are  found  in  the 
northeastern  portion  of  the  State.  Those  of  your  own  vicinity  are 
as  well  worthy  of  a  trial  for  this  result  as  any  known  to  me  in  the 
Mississippi  Valley,  and  specimens  were  collected  from  various  quar- 
ries in  your  region  with  a  view  to  having  them  analyzed  and  tested. 
It  must  be  remarked,  however,  that  the  only  reliable  tests  are  those 
which  may  be  made  at  an  ordinary  lime  -  kiln,  by  properly  burning 
the  rock,  and  afterward  grinding  it  very  fine,  and  then  by  practical 
trial  of  the  substance  produced.  When  it  has  been  determined  that 
any  rock  will  make  the  cement  desired,  the  necessary  skill  can  be 
readily  acquired  by  any  one  for  producing  it  in  any  quantity. 

"It  is  the  intention  of  Mr.  Mclsaac,  of  Waterloo,  to  make  some 
practical  tests  of  the  magnesian  limestones  of  your  vicinity  to  which 
I  have  referred." 

Within  the  last  two  months,  Mr.  Mclsaac  informed  me  that  although 


REPORT  OF  STATE  GEOLOGIST.  21 

a  press  of  business  had  prevented  him  from  making  the  proper  experi- 
ments, Mr.  Robert  B.  Brown,  of  Waverly,  Bremer  county,  had  been 
conducting  a  series  of  experiments  with  evident  success.  A  short 
time  afterward  Mr.  St.  John  called  on  Mr.  Brown,  and  obtained  for 
the  State  collections  a  full  suite  of  specimens  illustrating  his  experi- 
ments, and  from  which  it  seems  almost  certain  that  he  is  just  upon 
the  eve  of  complete  success  in  the  manufacture  of  hydraulic  cement 
of  excellent  quality,  although  the  practical  test  of  its  use  must  be 
made  before  such  a  decision  can  be  giv<^n.  In  view  of  the  energy 
with  which  Mr.  Brown  is  conducting  his  experiments,  we  may  hope 
to  know  the  full  result  before  the  close  of  the  present  year. 

Similar  references  were  made  to  the  magnesian  limestones  in  the 
vicinity  of  Cedar  Falls,  in  a  communication  about  the  same  time  to 
the  Ctdar  Falls  Gazette. 

Very  little  time  was  spent  in  Black  Hawk  county,  but  it  was  seen 
to  be  well  supplied  with  building -stone,  brick -clays,  forest -wood, 
excellent  water,  almost  unlimited  water-power,  and  as  to  its  soil,  it 
is  already  high  praise  when  it  is  said  that  it  is  a  part  of  the  Valley 
of  the  Cedar. 

HARDIN  COUNTY. 

Crossing  from  the  Cedar  to  the  Iowa  river,  the  extreme  northeast- 
ern corner  of  the  coal-field  was  visited,  in  the  vicinity  of  Eldora, 
Hardin  county.  Commencing  examinations  at  Iowa  Falls  in  the 
northern  part  of  the  county,  the  following  was  soon  after  communi- 
cated to  the  Iowa  Falls  Sentinel : 

The  rocks  exposed  along  the  river  near  Iowa  Falls  belong  to  the 
lower  portion  of  the  sub  -  carboniferous,  group,  and  are  consequently 
older  than,  and  below  the  coal.  Standing  at  the  mill  in  the  village 
and  looking  across  the  river,  you  will  see  that  the  strata  dip  from 
that  point  both  eastward  and  westward,  their  most  elevated  point, 
which  geologists  call  an  anti  -  clinal  axis,  being  just  where  you  stand. 
The  eastward  dip  does  not  probably  extend  far,  before  the  strata 
gradually  rise  again.  The  westward  dip  is  so  great  that  a  little  above 
Talbott's  mill,  three  miles  from  town,  all  the  strata  which  you  can  see 
in  the  village  have  passed  nearly  out  of  sight  beneath  the  river,  and 
begin  there  to  receive  the  coal -measure  deposits  upon  them,  but  that 


22  REPORT  OF  STATE  GEOLOGIST. 

any  coal  exists  among  them,  remains  to  be  decided  by  boring  or 
digging.  My  opportunity  for  examining  this  locality  was  not  satis- 
factory, but  judging  from  the  fact  that  it  is  just  upon  the  border  of 
the  coal  -  field,  and  in  a  local  depression,  since  the  Iowa  Falls  strata 
rise  and  appear  again  at  Alden,  the  prospects  for  obtaining  coal  in 
paying  quantities  at  or  near  Talbott's  mill,  are  not  believed  to  be 
promising. 

The  close  proximity  of  the  Eldora  coal,  however,  and  the  existence 
of  the  large  body  of  timber  westward  of  Iowa  Falls,  give  you  a  great 
advantage  over  many  other  towns  of  the  State,  in  a  plentiful  supply 
of  fuel.  Considering  the  large  tracts  of  country  on  which  no  stone, 
certainly  no  limestone,  is  to  be  seen,  you  possess  another  great 
advantage  in  the  large  exposures  of  excellent  limestone,  which,  figu- 
ratively speaking,  nature  seems  to  have  lifted  out  of  the  earth  just 
at  that  point  for  your  especial  benefit,  but  in  doing  this  she  deprived 
you  of  the  coal  which  was  bestowed  upon  your  neighbors  of  the 
southern  part  of  the  county.  All  the  strata  exposed  along  the  river 
in  the  village  are  composed  of  a  good  and  comparatively  pure  lime- 
stone, all  of  which  will  make  good  lime,  and  many  of  which  furnish 
excellent  stone  for  dressing.  The  rough,  fragmentary  stone  of  a 
yellowish  color,  seen  in  the  hills  around,  and  to  the  southeastward  of 
the  village,  are  magnesian  limestone,  although  they  look  like,  and  are 
frequently  called  sandstone.  This  stone  is  probably  useless  except 
for  the  roughest  masonry,  but  since  good  stone  is  so  abundant,  this  is 
not  needed. 

The  following  is  a  part  of  a  communication  to  the  Eldora  Ledger, 
communicated  June  6,  1866  : 

The  rocks  exposed  along  the  river  at  Iowa  Falls,  as  do  also  the 
rough  fragmentary  layers  in  the  hills  around,  and  southeastward  of 
the  village,  which  overlie  them,  all  dip  to  the  southward,  in  which 
direction  the  lower  ones  soon  disappear,  but  the  upper  portion,  which 
is  highly  magnesian  and  at  Hardin  City,  contains  considerable  iron 
and  some  sand,  can  be  traced  as  far  as  the  village  of  Steamboat 
Rock,  where  they  suddenly  disappear  and  the  coal-measure  sandstone 
as  suddenly  makes  its  appearance. 

Within  a  mile  of  this  first  appearance  of  the  sandstone,  it  presents 
a  perpendicular  front  of  some  seventy  -  five  feet  on  the  left  bank 


REPORT  OF  STATE  GEOLOGIST.  23 

of  the  Iowa  river ;  and  within  two  miles  on  a  straight  line  from  the 
locality  where  the  coal  -  measure  rocks  first  appear,  they  reach  a 
development  of  nearly  or  quite  two  hundred  feet  in  thickness,  as 
seen  in  the  hill,  and  by  the  boring  at  Buckner's  coal  mine.  This  is 
a  very  remarkable  development  of  strata  so  near  the  well  defined 
border  of  the  coal-field,  and  causes  some  hesitation  in  giving  a 
positive  opinion  as  to  the  relative  position  of  the  underlying  rocks 
of  the  immediate  neighborhood,  before  a  very  careful  examination  is 
made.  And  there  are  also  evidences  of  a  slight  local  and  irregular 
dip  of  the  whole  region,  to  the  southward.  Just  at  Buckner's  mine 
there  seems  to  be  a  local  longitudinal  depression,  extending  thence  a 
little  east  of  south,  so  that  the  strata  probably  dip  slightly  both 
east  and  west  toward  the  axis  of  it.  Along  this  axis  the  bed  of  coal 
appears  to  bo  below  the  level  of  the  river,  but  elsewhere  it  is 
doubtless  above  it. 

Exposures  of  coal-measure  strata  were  observed  in  the  region 
surrounding  Buckner's  mine  indicating  that  they  underlie  a  surface 
of  some  two  square  miles,  and  doubtless  more,  but  how  far  the  bed 
of  coal  now  worked  extends,  and  what  is  its  thickness,  in  continua- 
tion, has  not  been  determined,  except  at  the  few  points  where  it  has 
been  mined.  To  prove  this  I  have  suggested  to  some  parties 
interested,  to  bore  down  to  the  coal  in  various  places  as  the  only 
practicable  method  of  determining  the  facts,  and  one  that  will  be 
decisive. 

Experience  has  shown  that  the  quality  of  a  bed  of  coal  is  generally 
better  beneath  a  high  unbroken  hill,  than  where  the  overlying 
material  is  thin  and  uneven.  In  view  of  this,  and  the  fact  that  the 
coal-bed  seems  to  thicken  to  the  northward  at  Buckner's  mine,  I 
have  suggested  that  several  borings  be  made  on  the  hill  in  different 
directions  and  at  various  distances  from  the  mine. 

It  is  equally  desirable  also,  to  prove  in  the  same  manner,  the 
region  to  the  westward  and  southward  to  the  distance  of  about  a 
mile  in  each  direction,  and  it  is  not  at  all  improbable  that  a  bed  of 
coal  may  be  found  beneath  Eldora,  but  if  so,  it  will  be  at  a  con- 
siderable depth.  If  one  exists  there,  nothing  can  be  known  of  its 
character  without  boring. 


24  REPORT  OF  STATE  GEOLOGIST. 

Judging  from  the  indications  observed,  I  was  led  to  believe  that 
the  best  prospect  for  obtaining  coal  in  this  region,  is  found  along  the 
left  bank  of  the  river,  from  a  point  somewhat  west  of  Backner's 
mine,  to  about  a  quarter  of  a  mile  below  it;  but  boring  at  various 
points  from  a  mile  below  Steamboat  Rock,  to  the  mouth  of  Pine 
Creek,  may  reveal  as  gojd  or  better  indications  elsewhere. 

Mr.  Buckner  is  now  boring  for  a  lower  bed  of  coal  at  his  mines, 
having  reached  a  depth  of  nearly  a  hundred  feet  below  the  bed  he  is 
now  working.  The  drill  has  passed  most  of  the  way  through  a  blue 
shale  common  to  the  coal-measures.  Should  the  drill  reach  limestone, 
the  boring  ought  to  be  stopped  at  once,  for  there  is  no  doubt  that  it 
would  prove  to  be  sub  -  carboniferous  limestone,  below  which  it  is 
useless  to  look  for  coal. 

The  quality  of  the  coal  at  Buckner's  mine,  the  only  one  now 
worked,  is  fair,  and  if  properly  separated  from  the  sulphuret  of  iron, 
it  is  as  good  as  Western  coal  will  average.  About  a  foot  of  the 
lower  portion  of  the  bed  is  very  good,  and  carefully  selected,  will  be 
suitable  for  working  iron,  and  the  preparation  of  illuminating  gas. 
The  bed  is  four  feet  in  thickness  and  the  working  is  now  done  along 
two  narrow  passages  which  have  not  yet  penetrated  far  into  the  hill. 
It  is  the  intention  of  those  who  are  conducting  the  operations  to 
carry  the  work  in  the  same  direction  all  along  the  inner  side,  thus 
proceeding  beneath  the.  hill,  letting  most  of  the  roof  fall  in  behind 
them  as  they  remove  the  temporary  supporting-posts.  This  plan 
gives  them  an  opportunity  to  assort  the  coal  in  the  mine,  and  throw 
the  refuse  behind  them.  They  can  also  remove  the  coal  more 
expeditiously  and  cheaper  in  this  way  than  in  any  other. 

Within  a  few  days  after  the  foregoing  communication  was  pub- 
lished, Mr.  Buckner  resumed  his  boring,  and  his  drill  soon  reached 
the  limestone  referred  to,  when  he  promptly  stopped  the  work  with- 
out finding  any  coal  beneath  the  bed  he  was  then  working. 

The  advantage  possessed  by  the  owners  of  the  Eldora  coal  mines 
is  very  great,  from  the  fact  that  they  are  situated  in  a  prominent 
angle  of  the  coal  field,  which  gives  them  an  unusually  extensive 
market.  Besides  these  coal  mines,  Hardin  county  has  a  plentiful 
supply  of  wood  for  fuel  also.  Upon  the  sandstone  cliffs  in  the 
vicinity  of  the  coal  mines,  the  white  pine  and  white  birch  arc  both 


REPORT  OF  STATE  GEOLOGIST.  25 

observed,  which  are  very  unusual  in  this  part  of  the  State,  and  is 
believed  to  be  the  southern  limit,  at  least  of  the  birch.  Hon.  C.  F. 
Clarkson  has  successfully  transplanted  quite  a  number  of  both  of 
these  trees  to  the  grounds  around  his  residence,  a  few  miles  away, 
where  they  are  growing  thriftily  upon  prairie  soil,  and  where  he  has 
already  proven,  if  proof  be  needed,  that  all  kinds  of  our  indigenous 
trees  will  thrive  upon  our  prairies,  if  they  are  protected  from  the 
annual  fires. 

HAMILTON  COUNTY. 

Proceeding  westward,  the  next  examinations  were  made  along 
Boone  River,  in  Hamilton  county.  It  was  desirable  that  the  expo- 
sures of  coal  along  the  northern  border  of  the  coal-field  should  be 
examined,  for  the  purpose  of  comparison  with  those  of  the  southern, 
central  and  western  parts,  the  better  to  understand  the  character  of 
the  different  beds,  and  their  mode  of  occurrence.  Our  coal-field  is  a 
very  large  one,  and  it  is  intended  to  devote  the  greater  part  of  the 
field-labor  of  the  next  two  years  to  its  examination.  The  results 
of  that  trip  were  quite  satisfactory,  because  a  better  development 
of  the  coal-measure  strata  was  found  along  the  northern  border  of 
the  coal-field,  and  the  coal  found  to  be  more  abundant  and  of  better 
quality  than  might  reasonably  have  been  inferred  before  examina- 
tion. While  at  Webster  City  I  was  informed  that  a  thin  bed  of  coal 
had  been  found  a  few  miles  north  of  town,  but  no  examinations  were 
made  in  that  direction.  It  is  not  impossible  that  coal  should  be 
found  there,  but  since  the  sub-carboniferous  rocks,  below  which  no 
coal  can  be  expected,  are  seen  in  the  river  banks  half  a  mile  below 
town,  and  the  general  dip  of  the  strata  being  to  the  southward, 
Webster  City  is  evidently  very  near  the  northern  boundary  of  the 
coal-field,  and  consequently  a  large  expenditure  of  money  in  the 
search  for  coal  in  that  direction  could  not  be  recommended. 

To  the  southward,  however,  along  Boone  River  and  some  of  its 
tributary  creeks,  the  case  is  quite  different,  for  here  large  quantities 
of  coal  exist,  as  may  be  seen  by  any  one  who  will  take  the  trouble 
to  go  to  the  localities,  where  it  is  to  be  seen  in  natural  exposures  in 
the  hill  sides. 
4: 


25  REPORT  OF  STATE  GEOLOGIST. 

Going  down  Boone  River,  the  first  exposure  seen  was  on  the  right 
bank,  in  the  hill  side,  about  four  miles  from  town.  The  coal  is  of 
good  quality,  has  been  worked  to  a  considerable  extent,  and  the  bed 
is  said  to  be  four  feet  thick,  which  no  reason  was  seen  to  doubt. 
Between  this  point  and  Sternberg's  mill,  which  is  six  miles  from 
town,  the  same  bed  of  bituminous  coal  again  appears,  as  docs  a  bed 
of  cannel  coal,  two  feet  in  thickness  and  of  fair  quality.  The  latter 
bed  lies  several  feet  beneath  the  former,  and  is,  of  course,  no  way 
connected  with  it.  Near  Sternberg's  mill  and  also  at  various  points 
for  a  number  of  miles  below  the  mill,  the  coal  makes  its  appearance 
in  the  banks  where  they  are  rendered  steep  by  the  washing  of  the 
river.  These  beds  are  doubtless  continuous  in  broad  continuous 
layers  beneath  the  surface,  over  a  large  area,  and  have  become  ex- 
posed to  view  in  places  by  the  deepening  of  the  river  valley  by  its 
own  stream.  They  may  doubtless  be  reached  with  comparatively 
little  labor  from  the  gentler  slopes  of  the  river  valley,  and  when  the 
demand  will  warrant  it,  as  it  probably  will  in  the  future,  they  may 
be  mined  by  sinking  shafts  to  them  from  the  higher  lands  away  from 
the  river.  As  much  attention  as  possible  was  given  to  the  quality  of 
the  coal,  and  the  conclusion  arrived  at  is,  that  the  coal  along  Boone 
river  is  fully  equal  to  the  average  of  Western  coal.  None  was  seen 
in  this  region  which  contains  so  much  sulphur  and  other  impurities, 
as  many  beds  do  which  are  profitably  worked  in  other  places.  It 
was  noticed  that  very  few  of  the  inhabitants  were  using  coal  for  fuel, 
but  this  was  fully  explained  by  the  fact  that  no  regular  system  of 
mining  is  adopted,  and  the  supply  is  consequently  too  uncertain  to 
be  depended  on. 

This  supply  is  also  at  present  rendered  somewhat  unnecessary  by 
the  abundant  growth  of  excellent  timber  which  the  region  affords, 
but  with  its  present  rapid  settlement,  and  the  prospect  of  the  early 
extension  of  the  Dubuque  and  Sioux  City  Railroad,  the  case  will  soon 
be  different,  and  large  quantities  of  coal  will  then  be  demanded  for 
the  regions  eastward  and  northward  of  Webster  City.  This  want 
must  be  supplied  in  great  measure  by  the  Boone  river  coal-mines. 

WEBSTER  COUNTY. 
After  going  down  Boone  river  about  twelve  miles  from  Webster 


REPORT  OF  STATE  GEOLOGIST.  27 

City,  we  crossed  over  to  the  Des  Moines,  examining  a  number  of  coal 
exposures  along  that  river  and  its  tributaries  on  our  way  up  to  Fort 
Dodge.  Near  this  place  the  coal  and  gypsum  were  briefly  examined, 
but  since  the  region  was  subsequently  examined  with  more  care,  a 
fuller  account  of  its  resources  will  be  found  on  another  page. 

One  can  not  visit  the  valleys  of  the  rivers  referred  to  in  the  pre- 
ceding pages  without  being  impressed  with  the  fact  that  they  are 
destined  to  be  soon  filled  with  a  wealthy  and  prosperous  population, 
and  to  be  the  seat  of  thousands  of  happy  homes;  and  there  seems  no 
reason  to  believe  that  future  bards  may  not  arise  to  sing  the  beauties 
of  the  Cedar,  the  Iowa,  the  Boone  and  Des  Moines,  since  many  a 
stream  has  become  famous  in  song  which  does  not  possess  half  their 
native  beauties. 

Returning  to  prepare  the  outfit  for  the  work  in  the  western  part  of 
the  State,  a  short  time  was  spent  in 

JONES  COUNTY. 

Time  would  not  permit  the  full  examination  of  Jones  county  at  the 
time  it  was  visited,  but  the  long  and  favorably  known  quarries  near 
Anamosa  received  an  examination,  and  the  following  account  of  them 
was  sent  to  the  Anamosa  Eureka  in  May,  1866  : 

Although  Jones  county  is  entirely  beyond  the  limits  of  the  great 
Iowa  coal  -  field,  yet  the  large  bodies  of  timber  along  the  Wapsipincon 
and  Maquoketa  rivers  will  yield  a  plentiful  supply  of  fuel  for  all  time 
to  come.  The  supply  is  now  more  than  sufficient,  and  the  tendency 
of  the  forests  to  encroach  upon  the  prairies  where  the  fires  are  kept 
out,  is  apparent  to  every  one,  so  that  the  increase  in  this  respect  will 
supply  the  demands  of  an  increasing  population. 

An  examination  of  the  brick  of  several  houses  in  your  place  shows 
that  you  have  a  supply  which  is  good,  and  no  doubt  abundant,  of  this 
indispensable  building  material. 

The  soil,  as  far  as  seen,  is  a  rich  dark  loam,  containing  just  enough 
sand  to  make  it  warm  and  mellow,  without  approaching  barrenness ; 
and  that  much  of  the  material  having  a  sandy  appearance,  is  really 
not  silicious  in  its  composition  but  results  from  the  disintegration  of 
the  magnesian  limestones  which  underlie  the  county. 

Thoss  who  have  visited  the  lead  mines  of  Dubuque,  have  seen 


2£  REPORT  OF  STATE  GEOLOGIST. 

large  quantities  of  material  thrown  out  of  the  diggings  near  the 
surface,  which  has  the  appearance  of  sand,  but  in  reality  contains 
none  at  all ;  for  it  is  composed  of  the  disintegrated  rock  from  which 
the  lead  ore  is  obtained,  which  is  also  a  magnesian  limestone,  although 
it  belongs  to  a  different  geological  period  from  that  which  underlies 
Jones  county.  Some  of  your  readers,  who  learned  their  mineralogy 
from  Comstock's  manual,  will  remember  that  under  the  head  of 
Magnesian  Limestone  he  has  the  following  paragraph  :  "  Where 
magnesia  exists  in  considerable  quantity  in  the  soil,  it  wholly  destroys 
vegetation."  This  statement  is  now  known  to  be  entirely  without 
foundation  in  fact,  of  which  the  people  of  the  northwestern  part  of 
our  State  have  the  fullest  evidence  from  the  fact  that,  although  their 
soil  is  almost  entirely  underlaid  by,  and  largely  derived  from 
magnesian  limestone,  it  is  nevertheless,  as  a  whole,  as  productive  as 
any  with  which  a  beneficent  Creator  has  spread  the  earth.  However, 
since  the  world  owes  so  much  to  the  labors  of  scientific  men,  we 
ought  in  justice  to  forgive  their  occasional  errors  and  strive  to 
correct  them. 

Nearly  all  the  rocks  of  Jones  county,  belong  to  the  Upper  Silurian 
age,  and  those  in  the  vicinity  of  Anamosa  are  believed  to  be  geo- 
logically the  highest  of  that  age  occurring  in  the  State,  but  I  had 
not  time  to  satisfy  myself  fully  upon  these  geological  questions,  and 
consequently  felt  constrained  to  devote  all  the  time  at  my  disposal 
to  matters  of  immediate  practical  importance  to  the  people.  The 
beds  of  rock  exposed  along  the  river  in  your  city,  are  thought  to  be 
continuous  with  those  at  the  quarries  three  miles  distant,  although 
the  stratification  is  quite  different.  Notwithstanding  this  difference, 
the  chemical  composition  and  contained  fossils  are  nearly  or  quite 
the  same,  and  the  peculiar  stratification  which  is  so  valuable  a 
character  at  the  quarries,  seems  to  be  confined,  so  far  as  could  be 
ascertained,  to  an  area  not  much,  if  any,  more  than  three  miles  in 
extent. 

Although  this  area  is  thus  limited,  the  supply  of  excellent  stone 
is  practically  unlimited.  It  would  surprise  one  wrho  knows  the 
reputation  that  this  stone  has  already  obtained  abroad,  to  visit  the 
quarry  and  learn  the  fact  that  all  the  stone  which  has  yet  been  taken 


REPORT  OF  STATE  GEOLOGIST.  29 

out  for  the  home  and  distant  markets,  has  only  just  opened  one 
quarry  to  a  degree  that  lays  bare  the  best  and  most  profitable  layers, 
and  two  or  three  others  which  can  hardly  be  said  to  be  yet  opened. 

This  principal  quarry  is  now  owned  and  worked  by  Messrs.  Haines 
&  Co.,  and  is  generally  known  as  the  "  Anamosa  Quarry."  Two 
and  a  half  miles  northeast  of  this  point,  Mr.  John  Burham  has  long 
had  a  quarry  in  operation,  but  I  did  not  get  time  to  visit  it. 

Messrs.  Parsons  &  Webb  have  just  commenced  opening  a  quarry 
one  and  a  half  miles  west  of  the  "  Anamosa  Quarry,"  adjoining  the 
railroad,  with  good  indications  of  procuring  a  large  supply  of  excel- 
lent stone.  These  gentlemen  have  also  commenced  the  erection  of  a 
large  kiln  for  the  manufacture  of  lime  from  their  broken  stone. 
Samples  of  mortar  prepared  from  lime  made  from  this  stone  were 
seen  which  were  equal  in  quality  to  any.  It  is  intended  to  have 
some  of  the  layers  tested  for  the  purpose  of  learning  whether  it  may 
be  used  for  the  preparation  of  hydraulic  cement.  It  will  be 
remembered  that  some  of  the  best  of  these  cements  are  prepared 
from  magnesian  limestone. 

For  a  description  of  the  character  of  the  Anamosa  stone,  I  shall 
be  obliged  to  confine  myself  to  that  of  the  quarry  of  Messrs.  Haines 
&  Co.,  because  it  is  the  only  one  which  has  been  worked  to  a  sufficient 
extent  to  disclose  the  full  value  of  the  material ;  yet  there  is  every 
reason  to  believe  that  at  almost  any  point  in  the  hills  in  the  imme- 
mecliate  vicinity  the  same  quality  of  stone  will  be  obtained,  for  the 
layers  extend  horizontally  irrespective  of  the  unevermess  of  the  sur- 
face, the  only  questions  to  be  decided  are  as  to  the  amount  of  labor 
required  to  remove  the  superficial  material,  and  the  convenience  of 
shipping  the  stone  when  quarried. 

The  common  character  and  appearance  of  magnesian  limestone  in 
a  natural  exposure,  of  whatever  geological  age,  is  rough  and  pic- 
turesque, like  the  exposure  seen  on  each  side  of  the  Wapsipinicon 
just  below  your  mills;  but  the  stone  of  the  quarries,  although  mag- 
nesian, is  a  remarkable  exception  in  its  stratification.  It  is  fine 
grained,  evenly  and  horizontally  bedded,  some  of  the  layers  splitting 
readily  into  slabs  from  half  an  inch  to  one,  two,  three  or  four  inches 
in  thickness,  and  of  almost  any  desired  size  ;  many  of  which  are  as 
even  in  thickness  and  surface  as  a  board  from  a  planiiifj  machine 


30  REPORT  OF  STATE  GEOLOGIST. 

The  surface  of  a  few  of  the  layers  is  slightly  rough,  but  they  are 
very  uniform  in  thickness.  Some  of  the  layers  will  furnish  blocks 
four  feet  in  thickness  if  desired;  and  from  very  many  of  them  are 
obtained  almost  perfect  ashlars  for  caps  and  sills,  water  -  table,  store- 
front columns,  &c.  The  bedding  surfaces  are  so  smooth  and  true  in 
many  instances  as  not  to  require  to  be  touched  with  a  chisel. 

The  whole  front  exposed  at  this  quarry  is  about  ninety  feet  above 
the  river,  giving  just  room  enough  for  the  railroad  between  it  and 
the  quarry.  From  fifteen  to  twenty  feet  of  the  lower  beds  are  more 
porous  in  texture  than  those  above,  but  they  are  harder,  heavier,  and 
doubtless  fully  as  durable.  The  stone  of  the  upper  layers  is  rather 
soft  when  first  taken  out,  but  in  a  couple  of  days  it  becomes  quite 
hard  and  firm. 

The  weight  of  a  cubic  foot,  as  given  me  by  Mr.  Philip  Haines,  is, 
when  quite  dry,  140  Ibs.  for  the  upper  layers,  and  160  lj>s.  for  the 
lower. 

Of  the  present  and  prospective  value  of  these  quarries,  it  is  not 
easy  to  form  a  correct  estimate,  but  there  is  little  danger  of  placing 
it  too  high.  The  present  market  for  dressed  stone  and  slabs  extends 
from  Cedar  Rapids  to  Dubuque,  and  also  so  far  as  Independence  in 
Buchanan  county ;  and  as  the  population  increases  the  demand  will 
be  more  extended  and  much  greater  than  now,  for  there  are  no  simi- 
lar quarries  within  a  long  distance  from  this,  if  any  others  exist  in 
the  State. 

The  broken  stone  for  common  walls  finds  a  ready  market  at  the 
various  stations  along  the  whole  length  of  the  Dubuque  Southwestern 
Railroad,  although  the  ordinary  rough  stone  can  be  obtained  at  those 
points. 

The  great  advantage  of  these  stones  for  cellar  walls  is  that  they 
can  be  readily  joined  so  closely  that  rats  can  not  burrow  through 
them;  they  require  less  mortar  to  bed  them,  less  labor  to  lay  them, 
and  make  a  firm  and  stronger  wall.  The  broad  slabs  make  the  best 
walks  that  can  be  desired,  and  will  outlast  brick  for  that  purpose. 

BURLINGTON  AND  ITS  VICINITY. 

The  name  of  Burlington  will  be  known  wherever  American  geology 
is  studied,  because  the  " Burlington  limestone"  has  produced  a  greater 


REPORT  OF  STATE  GEOLOGIST.  31 

variety  of  interesting  fossils  than  any  other  known  locality  in  the 
•world.  Of  cririoids  alone,  more  than  three  hundred  species  as  at 
present  classified  have  been  found  in  the  limestones  of  that  vicin- 
ity. Beside  this,  more  than  one  hundred  species  of  other  fossils 
have  been  obtained  from  the  strita  which  underlie  the  Burlington 
limestone  at  the  same  locality.  The  rocks  which  constitute  the 
framework  of  the  high  bold  hills  around  Burlington  belong  to  the  two 
lower  members  of  the  sub -carboniferous  group,  namely,  the  Kinder- 
hook  series,  and  the  upper  and  lower  Burlington  limestone.  The 
former  consists  of  five  or  six  distinct  beds  of  limestones  and  fine- 
grained sandstones,  none  of  which  are  of  much  economic  value. 
The  two  groups  of  strata  composing  the  Burlington  limestone  contain 
material  of  the  greatest  value  in  building  the  city.  The  Kinderhook 
series  here  reaches  a  thickness  of  about  one  hundred  and  forty  feet, 
sixty  feet  of  which  was  ascertained  by  boring,  while  the  limestones 
rest  upon  it  and  form  the  bold  exposures  which  constitute  so  promi- 
nent a  feature  of  the  scenery  around  the  city.  The  Burlington 
limestone,  as  well  as  a  part  of  the  series  beneath  it,  are  to  be  seen 
in  the  bluffs  across  the  river  in  Illinois,  and  with  which  those  of  the 
Iowa  side  were  no  doubt  continuous  before  the  river  had  cut  its 
valley  down  to  its  present  depth,  and  to  a  width  of  six  miles  at  this 
point.  At  the  base  of  the  lower  Burlington  limestone  is  a  bed  of 
light  gray  limestone,  about  four  feet  in  thickness,  which  upon  close 
inspection  will  be  found  to  be  composed  of  minute  rounded  grains, 
and  is  called  in  geological  language  oolitic  limestone.  It  is  quarried 
and  wrought  with  facility,  and  has  a  good  appearance  when  cut,  but 
it  is  as  worthless  for  any  purpose,  except  the  preparation  of  lime,  as 
the  friable  sandstone  beneath  it;  for  it  is  sure  to  disintegrate  rapidly 
and  completely  upon  exposure  to  the  frost.  It  has  so  good  an 
appearance  when  taken  from  the  quarry,  and  can  be  obtained  in  such 
desirable  shapes,  that  it  has  been  used  for  paving  and  curbstones  in 
various  parts  of  the  city,  as  well  as  for  capping  embankment  walls, 
&c.,  and  in  every  instance  it  has  been  broken  up  and  destroyed  by 
the  action  of  the  frost  alone  within  a  year  or  two. 

The  heavy  beds  of  limestone  at  the  brow  of  the  bluffs  furnish  a 
great  part  of  the  paving  and  building  stone  used  in  the  city.  It  is 
unlimited  in  quantity,  is  not  affected  by  the  action  of  the  frost,  and 


32  REPORT  OF  STATE  GEOLOGIST. 

is  a  good  stone  for  ordinary  purposes,  but  the  upper  beds  of  lime- 
stone which  overlie  this,  although  they  do  not  appear  at  the  brow  of 
the  hills  within  the  city  limits,  furnish  so  much  fine  material  for 
hewn  stone  that  the  former  is  not  so  often  used  for  that  purpose  as 
it  otherwise  would  be.  These  upper  beds  are  seen  to  cap  the  bluffs 
below  the  city  a  few  miles,  but  many  of  the  quarries  opened  in  them 
are  in  the  southern  and  western  part  of  the  city,  and  also  beyond 
its  limits  in  those  directions.  This  stone,  when  hewn,  closely  resem- 
bles ia  color  the  worthless  limestone  before  referred  to,  but  close 
examination  will  show  that  it  has  none  of  that  peculiar  structure 
resembling  the  roe  of  a  fish,  which  the  worthless  stone  has.  The 
stone  of  these  upper  beds  is  of  a  pleasing  appearance,  as  durable 
as  the  everlasting  hills,  and  unlimited  in  quantity. 

The  quarry  of  Mr.  Nat.  Irvin,  in  these  beds,  has  furnished  a  large 
quantity  of  excellent  hewn  stone,  and  those  of  Mr.  Peter  Smith, 
farther  to  the  southwest  in  the  same  beds,  are  noted  for  the  excel- 
lent quality  of  lime  obtained  from  them.  The  quarries  of  Mr.  Parr, 
a  few  miles  below  the  city,  are  in  the  lower  beds  of  limestone,  con- 
tinuous with  those  at  the  brow  of  the  bluffs,  within  the  city  limits, 
the  lime  from  which  has  had  a  first-class  reputation.  But  good 
stone  is  so  abundant  here,  arid  quarries  so  numerous,  that  it  is  un- 
necessary to  make  more  definite  reference  to  them.  The  brick  -  clays 
upon  the  hills  are  abundant,  and  of  as  good  quality  as  any  to  be 
found  in  the  State.  Aside  from  the  materials  mentioned,  there  is 
little  probability  that  mineral  substances  of  economic  value  will  ever 
be  found  here. 

Since  the  rocks  of  this  vicinity  are  older  than  the  coal  -  measures, 
and  consequently  geologically  below  them,  there  is  no  hope  of  finding 
coal  here,  but  in  both  an  easterly  and  westerly  direction  they  pass 
beneath  the  surface,  and  have  received  the  coal  -  measure  deposits 
upon  them,  and  it  is  in  these  directions  that  one  must  go  to  procure 
a  supply  of  coal. 

The  coal  -  measure  rocks  do  not  appear  until  Skunk  river  is  passed, 
going  in  a  westerly  direction,  but  other  higher  members  of  the  sub- 
carbonifereus  group  are  found  to  lap  on  to  the  Burlington  limestone 
as  one  goes  in  that  direction.  The  Keokuk  limestone  is  next  in  the 
series  above  the  Burlington  limestone,  and  on  Long  Creek,  seven 


REPORT  OF  STATE  GEOLOGIST.  33 

miles  west  of  the  city,  some  important  quarries  in  that  limstone  are 
worked.  The  principal  quarry  is.  located  near  the  mouth  of  a  small 
branch  which  empties  into  Long  Creek,  a  few  hundred  yards  north 
of  the  ford,  and  consists  of  three  or  four  massive  layers  from  six  or 
eight  inches  to  two  or  three  feet  in  thickness.  Both  above  and  below 
those  layers  other  stone  is  seen,  but  it  is  of  little  or  no  economic 
value.  Although  the  stone  of  these  quarries  is  so  different  in  litho- 
logical  character  and  appearance  from  the  Keokuk  limestone,  as  seen 
at  Keokuk  and  Nauvoo,  they  are  nevertheless  a  part  of  that  forma- 
tion which,  extending  northward  from  the  places  named,  laps  upon 
the  Burlington  limestone,  os  the  latter  formation  dips  beneath  it  to 
the  southward  and  westward,  its  nearest  approach  to  Burlington 
being  on  the  Poor  -  House  Farm,  four  miles  from  the  city.  It  is 
quite  different,  also,  from  that  of  the  same  beds  in  the  immediate 
vicinity,  which,  although  continuous,  present  a  marked  change  within 
a  few  rods.  "While  in  the  city,  a  few  weeks  ago,  I  procured  a  speci- 
men of  the  rock  and  hal  it  analyzed.  Prof.  Hinrichs  reports  it  to 
be  highly  magnesian.  It  is  much  more  so  than  any  rock  of  the  same 
formation  in  this  vicinity  or  elsewhere,  but  less  so,  however,  than  the 
dolomites  of  northeastern  Iowa  ;  while  at  the  typical  localities  of  the 
same  formation,  Keokuk  and  Nauvoo,  it  contains  little,  if  any,  mag- 
nesia. 

This  stone  has  been  introduced  within  the  last  few  years,  and  has 
been  found  to  withstand  the  action  of  frost  better  than  any  other 
stone  obtained  in  this  vicinity.  It  presents  a  pleasant  appearance  in 
a  building,  and  is  much  used  for  caps,  sills,  water-tables,  store  -  fronts, 
&c.  It  is  hewn  rather  more  easily  than  the  light  grey  stone  of  the 
quarries  in  the  upper  portion  of  the  Burlington  limestone,  before 
mentioned,  and  which  has  heretofore  furnished  the  best  accessible 
material  for  such  purposes.  It  is  generally  of  a  uniform  texture,  and 
without  doubt  a  durable  and  valuable  stone,  perhaps  the  best  yet 
found  near  the  city.  Yet  it  has  occasionally,  but  not  frequently,  soft 
places  in  it,  which  should  be  avoided  in  hewing,  as  it  will  ultimately 
crumble  in  these  places  and  thus  deface  and  injure  the  structure. 
Although  the  exposures  of  stone  of  this  peculiar  character  are  limited 
in  extent,  yet  they  will  furnish  large  quantities  of  excellent  material 

for  many  years  to  come. 

5 


24  REPORT  OF  STATE  GEOLOGIST. 

We  are  accustomed  to  regard  limestone  as  one  of  the  most  inde- 
structible of  all  our  building  materials,  which  it  doubtless  is,  yet  the 
best  limestone  is  subject  to  more  or  less  erosion  by  "  the  tooth  of 
time,"  which  popular  expression  the  chemist  takes  the  poetry  out  of, 
by  telling  us  that  it  is  caused  by  carbonic  acid  taken  out  of  the 
atmosphere  by  the  falling  rains,  coming  in  contact  with  the  limestone, 
which  is  a  proto-carbonate,  constantly  changing  minute  quantities  of 
it  to  a  bi-carbonate,  which  is  soluble  in  cold  water,  but  the  lime 
becomes  precipitated  again  as  a  proto-carbonate,  or  common  limestone, 
when  exposed  to  the  atmosphere,  or  to  an  elevated  temperature.  We 
find  it  thus  deposited  as  stalactites,  and  stalagmites  in  caves ;  as  a 
rough  porous  limestone  where  some  springs  issue  from  the  earth 
and  also  often  forming  a  heavy  white  lining  to  our  tea  -  kettles.  Thus 
it  will  be  seen  that  when  even  the  rocks  are  disintegrated  they  are 
not  destroyed,  but  new  combinations  are  formed  from  the  same 
materials.  It  is  not  in  the  laboratory  alone  that  chemical  changes 
are  produced,  but  they  are  constantly  going  on  around  us,  and  it  is 
always  interesting,  and  sometimes  profitable  to  trace  them. 

Those  who  are  scientifically  or  curiously  inclined  may  observe 
some  interesting  results  of  such  chemical  changes  in  nature,  beneath 
the  overhanging  bluffs  at  Starr's  mill,  three  miles  northwestward 
from  Burlington.  That  portion  of  the  strata  which  is  seen  to  be 
more  rapidly  disintegrating  than  the  other,  and  leaving  the  solid 
limestone  projecting  above  contains  considerable  quantities,  both  of 
carbonate  of  magnesia  and  sulphuret  of  iron.  The  oxidation  of  the 
sulphur  produces  sulphuric  acid,  which  uniting  with  the  magnesia  by 
displacing  the  carbonic  acid,  forms  native  sulphate  of  magnesia. 
This  substance  is,  no  doubt,  formed  in  other  places,  but  being  very 
soluble  it  is  usually  carried  off  by  the  rains,  and  thence  by  the 
streams  to  the  sea,  the  waters  of  which  are  known  to  contain  large 
quantities.  But  here  the  overhanging  cliff  prevents  the  rain  from 
reaching  it,  beneath  which  it  is  found  as  a  white  encrustation  upon 
the  stones  among  the  fine  substance  resulting  from  the  decomposition 
of  rock.  By  re  -  dissolving  some  of  this  native  sulphate  of  magnesia, 
and  allowing  it  to  crystalize,  as  fine  a  sample  of  epsom  salts  was 
produced  as  can  be  purchased  at  any  of  our  drug  stores.  It  is 


REPORT  OF  STATE  GEOLOGIST.  35 

proper  to  say,  however,  that  this  substance  is  obtained  so  cheaply 
by  artificial  means,  that  small  quantities  of  it  may  be  regarded  only 
as  interesting  specimens  in  mineralogy. 

Des  Moines  county  is  abundantly  supplied  with  building  -  stone 
which  crop  out  in  almost  one  continuous  exposure  along  the  Missis- 
sippi river  bluffs,  from  the  northern  to  the  southern  line.  Also 
scarcely  less  abundantly,  along  Skunk  and  Flint  rivers,  Brush, 
Spring  and  Long  creeks. 

Its  other  advantages  are  too  well  known  to  need  mention  here. 

DAVIS  COUNTY. 

Davis  and  Appanoose  counties  received  only  partial  examinations 
at  the  time  they  were  visited,  because  the  plans  adopted  for  the  season 
contemplated  the  special  examination  of  the  southwestern  portion  of 
the  State  first. 

Upon  Salt  creek,  near  its  junction  with  Soap  creek,  where  the 
Bloomfield  road  crosses  the  former,  there  are  several  " salt-licks "  or 
springs,  from  which  samples  of  the  water  were  obtained  for  analysis. 
In  consequence  of  previous  continued  rains  they  were  flowing  freely. 
Therefore  the  water  was  proportionally  less  saline  than  usual.  Mr. 
S.  D.  Wells  afterward  sent  samples  from  another  spring  on  his  land 
in  the  same  neighborhood,  (Section  15,  70,  13,)  and  the  following  is 
the  result  of  a  preliminary  examination  by  Prof.  Hinrichs,  a  fuller 
account  of  which  will  be  found  in  the  Professor's  report  on  another 
page: 

The  water  of  the  first  named  spring  was  found  to  contain  soda, 
potassa,  lime,  iron,  alumina,  and  a  little  magnesia;  also,  chlorine  and 
sulphuric  acid.  These  substances  of  course  exist  in  combination 
with  each  other,  and  the  water  may,  from  present  indications,  be 
regarded  as  common  spring  water,  containing  common  salt,  alum,  ft 
little  copperas,  and,  as  is  usual  with  nearly  or  quite  all  the  spring 
waters  of  the  State,  a  considerable  proportion  of  lime. 

The  spring  on  Mr.  Wells'  farm  was  similar  to  the  other,  in  the 
character  of  its  water,  except  that  it  did  not  contain  so  great  a  pro- 
portion of  the  substances  named,  particularly  of  potassa,  while  the 
presence  of  iron  and  magnesia  were  not  detected  in  it. 

These  waters  have  some  characters  in  common  with  those  of  some 


36  REPORT  OF  STATE  GEOLOGIST. 

of  the  mineral  springs  resorted  to  for  medicinal  purposes,  but  in 
detail  they  vary  considerably  from  those  commonly  used.  The  spring 
on  Salt  creek  contains  a  considerable  proportion  of  salt,  but  probably 
not  enough  to  make  it  valuable  for  that  purpose. 

The  springs,  like  many  similar  ones  in  other  parts  of  the  coal-field 
of  the  State,  issue  from  the  shales,  limestones  and  clays  associated 
•with  the  coal. 

These  springs  are  a  favorite  resort  for  cattle  and  horses,  which 
drink  the  water  with  a  great  relish.  The  early  settlers  of  Davis 
county  used  to  shoot  many  deer  here,  where  they  came  in  great 
numbers  to  drink,  and  doubtless  long  departed  generations  of  Indians 
did  the  same. 

It  is  commonly  believed  that  springs  which  animals  resort  to  with 
unusual  avidity  always  contain  a  considerable  proportion  of  salt. 
But  this  is  not  the  case,  for  many  springs  are  known  which  contain 
an  amount  of  sulphuretted  hydrogen  that  renders  the  water  quite 
disagreeable  to  most  persons,  but  no  salt ;  yet  animals  become  very 
fond  of  such  water,  and  drink  with  as  much  eagerness  and  evident 
relish  as  they  do  saline  water. 

Davis  county  is  known  to  contain  large  quantities  of  excellent 
coal,  but  the  only  exposures  seen  were  one  nearly  four  feet  thick  a 
few  rods  below  the  spring  before  mentioned  on  Salt  Creek,  and 
another  half  a  mile  above  the  mill  of  Mr.  Peter  Hendricks,  on  Soap 
creek. 

A  foot  or  two  above  the  bed  of  coal  at  this  locality,  a  four  foot  bed 
of  compact,  bluish  limestone  is  found,  from  which  Mr.  Hendricks, 
some  years  ago,  manufactured  considerable  quantities  of  hydraulic 
cement.  Some  of  this  cement  was  used  in  the  construction  of  the 
locks  on  the  Des  Moines  River,  and  is  said  to  be  satisfactorily  tested. 
No  definite  analysis  of  this  rock  has  yet  been  made,  but  it  is  sup- 
posed that  its  hydraulic  property  is  due  to  alumnia  and  not  to  mag- 
nesia, like  that  of  the  northern  part  of  the  State. 

Beside  an  abundance  of  coal,  Davis  county  is  bountifully  supplied 
with  fuel  in  the  form  of  forest  trees. 

PETROLEUM. 
During  the  year  1865,  and  also  a  few  previous  years,  there  was 


REPORT  OF  STATE  GEOLOGIST.  37 

much  excitement  and  speculation  throughout  the  country  in  relation 
to  petroleum.  This  excitement  extended  even  to  our  own  State,  and 
resulted  in  much  useless  expenditure  of  money  in  the  search  for  oil. 
In  reply  to  numerous  inquiries  concerning  the  probabilities  of  finding 
petroleum  in  Iowa,  the  following  article,  slightly  modified  in  the 
wording,  but  not  in  character,  was  sent  to  three  or  four  of  the  news- 
papers of  the  State  on  June  15,  1866  : 

"  With  the  successful  boring  of  the  first  well  for  petroleum  in 
Titusville,  Pa.,  a  spirit  of  speculation  was  aroused,  or  rather  was 
given  a  new  direction,  which  went  on  increasing  as  one  success  fol- 
lowed another,  in  that  and  adjoining  States,  until  it  has  extended  not 
only  over  those  portions  of  our  country  where  the  search  for  petro- 
leum was  likely  to  be  attended  with  success,  but  also  to  regions 
where  success  could  not  possibly  reward  those  who  expended  their 
money  and  and  labor  in  such  enterprises.  Some  of  our  own  citizens 
caught  the  same  spirit,  and  commenced  the  search  for  this  valuable 
product,  but  thus  far  with  invariable  failure,  so  far  as  the  ultimate 
result  has  been  learned.  In  view  of  these  facts  my  opinion  has  been 
often  solicited  as  to  the  probability  of  finding  petroleum  in  paying 
quantities  in  our  own  State,  which  I  now  take  this  public  method  of 
stating,  together  with  the  reasons  for  entertaining  it.  The  impor- 
tance of  this  question,  as  well  as  of  the  responsibility  which  my 
official  position  imposes  upon  me,  are  well  considered;  but  it  is  be- 
lieved that  the  true  interests  of  the  people  of  Iowa  are  as  well 
served  by  informing  them  where  it  is  useless  to  expend  their  money 
as  they  would  be  by  directing  them  to  opportunities  of  making  profi- 
table investments. 

"  The  great  majority  of  the  men  engaged  in  the  search  for  petro- 
leum, have  commenced  the  enterprise  in  good  faith,  but  in  too  many 
instances  with  their  visions  blinded  by  bright  hopes  of  sudden  wealth ; 
honestly  inducing  others  to  join  in  the  expense  and  share  with  them 
the  great  profits  which  they  believed  themselves  sure  to  obtain.  But 
this  is  not  the  worst  feature  of  these  profitless  enterprises.  Design- 
ing men  have  induced  others  to  furnish  capital  for  prosecuting  the 
development,  or  purchase  of  reputed  oil  lands  which  perhaps  they 
themselves  had  "salted,"  or  rather  oiled;  or  concerning  the  great 
value  of  which  they, had  obtained  a  report  from  some  geologist  of 


33  REPORT  OF  STATE  GEOLOGIST. 

easy  virtue,  or  one  who  was  better  known  for  his  connection  with 
such  schemes  than  for  his  scientific  attainments.'7 

These  remarks  are  not  to  be  understood  as  in  any  respect  of  a  per- 
sonal character,  but  that  such  practices  have  been  committed,  is  too 
true  to  be  doubted.  Neither  have  I  any  words  of  disrespect  to  offer 
concerning  those  geologists  who  are  in  the  habit  of  examining  such 
lands  for  the  purpose  of  giving  an  honest  scientific  opinion  of  them. 
.  The  world  owes  much  to  such  men,  and  their  labors  are  often  under- 
estimated. 

First  then,  expenditures  of  money  and  labor,  should  be  made  with 
great  caution  in  our  State,  because  it  has  been  estimated,  and  I 
think  with  some  'reason,  that  every  dollar's  worth  of  petroleum 
obtained  in  the  United  States  has  cost  a  dollar  in  its  production.  If 
this  is  true  the  State  at  large  will  be  the  loser,  even  if  some 
individuals  are  successful,  because  there  is  no  reason  to  believe  that 
our  State  will  produce  at  best  even  an  average  amount  of  petroleum. 
The  primary  origin  of  petroleum,  is  believed  to  be  without  doubt  in 
fossilized  vegetable  substances,  —  probably  marine — which  existed 
and  accumulated  in  the  sediment  .which  now  forms  the  rock  from 
which  it  is  derived.  All  rocks  in  which  it  has  its  origin  as  such,  are 
highly  bituminious,  or  at  least  carbonaceous,  yet  it  is  often  obtained 
in  the  more  porous  rock  above  that  in  which  it  actually  originated. 

In  all  known  instances  where  petroleum  has  been  obtained  in  pay- 
ing quantity  in  the  United  States,  it  has  had  its  origin  in  heavy 
deposits  of  these  carbonaceous  strata;  no  slight  deposits  having  been 
known  to  produce  any  considerable  quantity,  even  when  very  rich  in 
the  carbonaceous  ingredient.  Sometimes  the  material  of  these  slight 
deposits  will  yield  petroleum  by  distillation,  but  as  a  natural  product, 
the  conditions  required  seem  in  all  cases  to  be  in  connection  with 
heavy  deposits  of  carbonaceous  strata,  and  at  considerable  depth 
beneath  the  surface. 

Although  the  illuminating  oil  formerly  obtained  by  the  distillation 
of  coal  is  the  same  in  its  chemical  composition  as  that  obtained  from 
petroleum ;  and  sometimes  petroleum  is  found  in  a  natural  state 
associated  with  coal  -  bearing  strata,  yet  in  the  great  majority  of 
instances  it  has  in  its  origin  no  connection  whatever  with  coal.  In 


REPORT  OF  STATE  GEOLOGIST.  39 

the  United  States  far  the  greatest  amount  of  petroleum  has  its  origin 
in  strata  of  Devonian  age, —  the  age  preceding  that  in  which  the 
coal  was  formed.  It  has  in  several  instances  been  found  in  rocks  of 
more  ancient  date  than  the  Devonian,  but  in  those  early  ages  it  is 
not  probable  that  vegetation  existed  in  sufficient  amount  to  produce 
the  carbon  which  is  believed  to  have  been  necessary  to  give  origin  to 
large  quantities  of  petroleum. 

Now,  in  applying  these  general  remarks  upon  the  origin  of  petro- 
leum to  our  State,  it  is  not  forgotten  that  it  has  not  yet  been  care- 
fully examined  in  all  its  parts,  but  enough  of  its  general  geology  is 
known  to  decide  the  fact,  with  scarcely  a  doubt  that  we  have  no  heavy 
deposits  of  carbonaceous  strata,  except  the  coal,  underlying  its  sur- 
face which  precludes  the  probability  of  obtaining  petroleum  beneath 
our  surface. 

Again,  when  it  has  been  found  in  connection  with  coal,  it  has  been 
with  cannel,  and  not  bituminous  coal.  We  have  a  few  beds  of  cannel 
coal  in  Iowa,  but  the  greater  part  is  bituminous.  Although  we  have 
coal  enough  in  Iowa  to  serve  a  crowded  population  for  many  genera- 
tions, yet  the  development  of  our  coal  strata  is  not  thick  enough  nor 
rich  enough  in  carbonaceous  matters,  I  think,  to  produce  petroleum 
in  paying  quantities.  That  what  are  usually  regarded  as  favorable 
indications,  and  that  small  quantities  of  it  have  and  may  yet  be 
found,  there  seems  no  reason  to  doubt.  Mr.  II.  T.  Woodman,  of 
Dubuque,  has  shown  me  some  light -brown  carbonaceous  shale  from 
the  Lower  Silurian  rocks  (Trenton  limestone)  near  Dubuque,  and 
also  some  similar  shale  from  the  same  beds  at  Shullsburg,  Wisconsin, 
which  will  burn  with  a  flame  equal  to  the  best  cannel  coal.  Similar 
shale  is  also  found  in  the  northeast  portion  of  the  State  in  the  so- 
called  Hudson  River  strata,  but  these  are  of  too  slight  development 
to  yield  any  considerable  amount  of  petroleum.  Both  of  these  de- 
posits doubtless  extend  beneath  the  surface  of  the  State  to  the  south- 
ward and  westward,  where  they  may  probably  be  reached  by  boring, 
but  it  is  not  believed  that  any  petroleum  would  be  obtained  from  them 
if  they  were  reached,  because  the  carbonaceous  deposit,  if  it  exists 
there,  is  doubtless  too  light  to  have  developed  it.  Time,  and  a 
further  collection  of  facts,  may  cause  a  change  in  the  opinion  here 


4Q  REPORT  OF  STATE  GEOLOGIST. 

expressed ;  but  with  the  possession  of  present  information,  I  am  not 
disposed  to  encourage  the  search  for  petroleum  in  Iowa." 

The  excitement  in  regard  to  petroleum  was  decreasing  when  the 
foregoing  article  was  written,  and  now  nothing  is  known  of  its  exist- 
ence anywhere  in  the  West. 

APPANOOSE  COUNTY. 

The  geology  of  Appanoose  county  may,  for  my  present  purposes, 
be  summed  up  in  these  few  words.  It  lies  wholly  within  the  great 
Iowa  and  Missouri  coal-field;  the  coal,  limestones,  sandstones,  and 
clays  of  which,  underlie  a  drift  deposit  of  varying  depth,  from 
twenty  to  perhaps  fifty  or  sixty  feet  upon  the  higher  lands ;  upon 
which  the  beautiful  and  fertile  soil  is  spread,  and  through  which  the 
streams  have  eroded  their  way  down  to  the  series  of  coal  -  measure 
rocks  just  mentioned. 

The  rocks  exposed  near  Centreville  are  believed  to  belong  to  both 
the  upper  and  middle  series  of  coal-measure  strata  as  sub-divided  by 
some  geologists,  the  limestones  belonging  to  the  former,  and  the 
coal  and  its  associated  shales,  to  the  latter.  If  this  is  the  case,  more 
coal  may  be  expected  to  exist  beneath  the  bed  now  worked  by  Mr. 
Talbot  at  his  mill  a  mile  from  town.  It  may  also  be  reasonably 
sought  for  on  the  lower  slopes  of  the  Chariton  valley,  particularly  in 
the  northern  and  northwestern  parts  of  the  county. 

Coal  has  been  mined  from  a  three-foot  be  1  at  several  points  in  the 
vicinity  of  Centreville.  The  only  mine  visited  was  that  at  Talbot's 
mill,  the  coal  of  which  was  found  to  be  of  superior  quality. 

Appanoose  county  is  well  supplied  with  everything  necessary  to 
make  a  community  prosperous  and  wealthy,  such  as  wood,  coal, 
building  -  stone,  brick  -  clays,  and  fertile  soil.  The  latter  seems  to 
have  been  largely  free  from  the  blighting  curse  of  non-resident 
land  owners. 

WAYNE  COUNTY. 

Those  whose  homes  are  in  less  beautiful  lands  than  Iowa,  and  who 
desire  to  understand  in  all  its  broad  expansiveness,  the  meaning  of 
the  word  "Prairie,"  should  visit  Wayne  county,  for  here  these  beautiful 
lineaments  in  the  features  of  our  mother  earth  are  to  be  seen  in  all 


REPORT  OF  STATE  GEOLOGIST.  4.1 

their  loveliness.  It  is  difficult  for  cne  who  has  never  seen  them  to 
form  a  correct  idea  of  their  character,  and  indeed  to  do  this,  one  must 
see  them  in  many  different  regions,  for  they  vary  much  in  this 
respect,  although  in  general  appearance  they  are  so  much  alike. 
Scientific  men  have  entertained  various  opinions  concerning  their 
origin,  many  of  which  were  circumscribed  by  their  want  of  opportu- 
nity to  observe  all  their  varieties.  Those  of  Iowa  are  nearly  all  such 
as  are  known  as  "  rolling  prairies,"  and  yet  those  of  the  northern 
and  western  parts  of  the  State  differ  from  each  other  in  character. 
This  difference  is  due,  in  part  at  least,  to  the  more  complete  drainage 
of  the  southern  portion,  and  this  drainage  is  due  to  the  deeper  erosion 
of  the  river  valleys  than  those  of  their  tributaries  farther  to  the 
northward.  When  the  continent  was  finally  raised  from  the  diluvial 
sea,  that  portion  of  it  which  is  now  our  state  doubtless  presented  a 
surface  which  was  only  slightly  undulating,  the  longitudinal  depres- 
sions of  which  were  in  the  same  direction  of,  and  gave  origin  to  the 
course  of  the  rivers  and  streams. 

Wayne  county  presents  an  excellent  example  of  a  well  -  drained 
prairie  region,  lying  as  it  Joes  where  the  Medicine,  and  the  South 
Fork  erf  Chariton  rivers  take  their  rise.  As  one  stands  upon  the 
prairie  in  the  central  part  of  the  county,  its  rolling  character  is 
somewhat  obscured  by  the  distant  view  which  is  only  broken  by  lines 
and  groves  of  forest  trees  that  reveal  the  presence  of  the  streams 
into  which  the  'surface  waters  are  gathered  by  the  multitude  of  gently 
sloping  and  gradually  deepening  ravines  which  give  the  prairies  of 
the  region  their  characteristic  rolling  appearance. 

The  fact  that  this  county  lies  about  the  head  waters  of  the  streams 
indicates  a  considerable  elevation,  but  this  is  not  definitely  known. 
That  of  Corydon,  however,  is  probably  not  far  from  the  same  as 
Chariton,  the  county  seat  of  Lucas  county,  which  is,  according  to 
Mr.  Thielson,  five  hundred  and  twenty  -  four  feet  above  the  level  of 
the  Mississippi  at  low  water  at  Burlington.  This,  added  to  four  hun- 
dred and  eighty  -  six  feet,  the  elevation  of  that  point  above  the  Gulf 
of  Mexico,  would  give  to  Corydon,  in  round  numbers,  an  elevation  of 
about  one  thousand  feet  above  the  level  of  the  sea.  The  soil  of 
Wayne  county  is  of  excellent  quality,  and  it  is  doubtful  if  an  equal 

area  can  be  found  any  where  having  so  little  waste  and  untillable 
6 


£2  REPORT  OF  STATE  GEOLOGIST. 

land.  The  only  elements  of  prosperity  wanting  here  are  a  sufficient 
supply  of  stone  and  timber.  The  heavy  deposit  of  drift,  which 
underlies  the  deep  soil,  renders  the  beds  of  stone  inaccessible,  which 
no  doubt  exist  at  too  great  a  depth  to  be  profitably  quarried.  This 
want  must  be  supplied  from  other  places,  and  by  the  manufacture  of 
brick. 

Timber  can  be  profitably  cultivated,  as  is  being  demonstrated  very 
extensively,  in  different  parts  of  the  State  ;  besides  which  the  natural 
growth  of  forest  trees  will  rapidly  encroach  upon  the  prairies  as  soon 
as  the  fires  are  kept  out.  Coal  of  good  quality  has  been  found  in 
the  northeastern  part  of  this  county,  and  a  few  exposures  of  stone 
are  also  seen  in  Wright,  and  South  Fork  townships,  but  depending 
on  these  alone,  little  could  be  said  of  its  geology,  except  that  it  is 
known  to  lie  within  the  great  Iowa  and  Missouri  coal-field,  as  do  also 
all  of  those  which  surround  it.  This  renders  it  entirely  reasonable 
to  prospect  for  coal  by  boring  at  almost  any  point  within  it.  Owing 
to  the  small  nnmber  of  exposures  of  the  series  of  strata  which  are 
generally  found  associated  with  the  beds  of  coal,  little  more  can  be 
suggeited,  than  that  borings  might  be  made  in  almost  any  part  of  the 
county  with  the  reasonable  hope  of  finding  coal  within  two  or  three 
hundred  feet  if  they  are  commenced  in  the  deeper  valleys.  It  is 
probable  also  that  the  upper  beds  of  coal  may  be  reached  within  one 
hundred  and  fifty  feet.  In  case  such  borings  are  undertaken,  it  is 
probable  that  a  considerable  thickness  of  limestone  would  be  passed 
through. 

DECATUR  COUNTY. 

Passing  westward  from  Wayne  to  Decatur  county,  one  observes 
a  marked  change  in  the  general  aspect  of  the  country,  which  is 
due  to  a  greater  proportion  of  timber  in  the  latter,  together  with 
the  existence  of  more  numerous  and  larger  streams.  Some  portions 
also  of  Decatur  county  are  more  uneven,  but  this  unevenness  is 
principally  confined  to  the  wooded  lands  in  the  vicinity  of  the  rivers, 
while  much  of  it  is  covered  with  prairies  of  that  peculiar  beauty 
which  characterizes  Wayne. 

The  same  geological  formations  also  underlie  both  counties,  but 
in  Decatur  the  rivers  have  eroded  their  channels  deeper  into  them 


REPORT  OF  STATE  GEOLOGIST.  43 

than  they  have  in  Wayne,  where  the  streams  are  comparatively  small. 
It  is  this  alone  that  has  produced  the  difference  in  the  character  of 
their  surfaces. 

All  the  rocks  of  Decatur  county,  at  least  those  above  the  level  of 
Grand  River  Bottom,  are  understood  to  belong  to  the  upper  or  unpro- 
ductive coal-measures.  Thus  far  no  coal  has  been  found  in  this  county, 
but  there  are  good  geological  reasons  for  believing  that  it  does  exist 
there  at  considerable  depth  beneath  the  surface.  Should  explorations 
be  made,  it  should  be  done  by  sinking  shafts.  These  ought  to  be  com- 
menced in  the  deeper  valleys,  for  it  is  believed  that  the  higher  strata 
do  not  contain  any  coal ;  and  since  the  strata  of  the  county  are  prac- 
tically level,  by  commencing  in  the  valleys  the  labor  and  expense  of 
digging  through  the  upper  strata,  which  are  largely  composed  of 
limestone,  would  be  avoided.  The  upper  coal -measure  limestone  just 
referred  to  affords  a  great  abundance  of  excellent  building  -  stone, 
more  particularly  along  Grand  Hiver  and  its  tributaries.  Should 
coal  never  be  found  in  Decatur  county,  its  inhabitants  will  never 
want  for  fuel,  because  it  is  well  supplied  with  a  thrifty  growth  of 
forest  trees.  The  county  is  well  watered  by  its  springs  and  nume- 
rous streams,  and  its  soil  has  no  superior  for  fertility. 

Little  has  heretofore  been  said  of  the  natural  beauties  of  the  regions 
thus  far  passed  through.  It  is  not  because  they  were  found  below  the 
average  in  this  respect ;  but  upon  this  bright  June  morning,  in  our 
journey  down  the  west  side  of  the  valley  of  Grand  River,  our  eyes 
have  been  resting  upon  views  of  impressive  loveliness.  The  wooded 
hillsides,  sloping  down  to  the  river  from  the  prairied  highlands  ;  the 
bottom  prairie,  level  as  a  floor;  the  belts  of  heavy  timber  skirting 
the  stream,  are  characters  in  the  landscape  peculiar  to  the  West,  and 
around  which  the  affections  of  the  children  reared  amid  these  scenes 
will  cling  as  long  as  memory  lasts. 

RINGGOLD   COUNTY. 

Wayne  has  been  described  as  a  prairie  county,  while  Decatur, 
adjoining  it  on  the  west,  is  found  to  possess  a  well  -  proportioned 
diversity  of  prairie  and  timber  land.  Proceeding  still  further  west- 
ward, Ringgold  county  again  presents  us  with  extensive  and  almost 
continuous  prairies  which,  however  differ  somewhat  in  character  from 


4  j.  REPORT  OF  STATE  GEOLOGIST. 

those  of  Wayne ;  in  consequence  of  the  difference  in  the  drainage 
systems  of  each,  and  not  to  any  material  difference  in  the  character 
of  their  formations. 

The  drift  -  deposit  in  Ringgold  county  is  very  thick,  and  its  distinc- 
tive topographical  features  are  produced  by  the  great  depth  to  which 
its  streams  cut  their  valleys  into  that  formation. 

Wayne  county  is  drained  in  almost  all  directions  from  its  central 
portions,  by  the  upper  branches  of  Chariton  and  Medicine  rivers, 
most  of  which  pass  out  of  the  county  before  they  have  increased  to 
any  considerable  volume,  and  before  they  have  eroded  their  valleys 
to  so  great  a  depth  that  the  tops  of  the  trees  which  skirt  them  can 
not  be  seen  peering  above  the  general  surface  as  one  stands  upon  the 
higher  prairie  levels. 

The  streams  of  Ringgold  county,  however,  pass  through  it  from  a 
northerly  to  a  southerly  direction,  having  at  the  northern  border  of 
the  county  already  attained  considerable  size,  and  in  their  passage 
through  it,  have  eroded  their  valleys  so  deeply  that  the  full  -  grown 
forest  trees  which  skirt  their  banks  can  not  be  seen  from  the  higher 
prairie  surface.  Indeed  they  could  not  be  thus  seen  in  many  cases 
if  they  were  three  times  as  high  as  they  are,  for  the  valleys  are 
usually  narrow,  with  somewhat  abrupt  slopes  to  the  prairie  level,  and 
from  one  hundred  to  two  hundred  feet  deep. 

Timber  is  usually  scarce  in  this  county,  but  along  the  Platte,  and 
East  and  West  Grand  rivers  there  are  considerable  bodies  of  forest 
trees  consisting  of  oak,  elm,  maple,  linden,  cottonwood,  hickory, 
buckeye,  black  walnut,  box  elder,  &c. 

Most  of  the  roads  are  excellent,  being  located  upon  the  "  divides," 
and  as  the  traveler  passes  over  them  there  is  very  little  upon  which 
the  eye  can  rest  to  relieve  the  monotonous  expanse  of  prairie  ;  and 
if  a  stranger  he  is  quite  unconscious  of  the  presence  within  the 
range  of  his  vision  of  these  deep  valleys  with  their  wooded  banks, 
until  he  approaches  to  cross  them,  which  being  done  they  are  again 
hidden  from  view,  and  the  course  of  the  valley  itself  obscured  by 
the  general  undulatory  character  of  the  surface. 

It  is  difficult,  if  not  impossible,  to  ascertain  accurately  the 
depth  of  the  drift  deposit  in  this  county,  but  it  is  probably  not  less 


REPORT  OF  STATE  GEOLOGIST.  45 

than  one  hundred  and  fifty  feet  deep  where  none  of  it  has  been 
removed  by  erosion.  Indeed  it  can  not  be  certainly  known  that  it  is 
not  fully  as  deep  as  the  full  depth  of  the  valleys  before  mentioned, 
for  no  other  material  appears  upon  the  slopes,  and  the  only 
exposures  of  rock  to  be  found  in  the  county  are  a  few  small  quarries 
of  upper  coal  -  measure  limestone  near  the  Missouri  border,  on 
section  19,  township  67,  range  29,  together  with  a  few  similar 
exposures  in  the  extreme  northeast  corner  of  the  county.  There 
are  at  least  five  hundred  and  fifty  square  miles  of  this  county  upon 
which  no  rocks  appear  except  the  very  few  boulders  associated  with 
the  drift.  It  will  be  thus  seen  that  a  geological  examination  of 
such  a  county  alone,  disconnected  from  adjoining  territory  would 
give  very  unsatisfactory  results,  except  of  the  character  of  the 
surface.  In  view  of  this  a  detour  was  made  to  the  northward  into 
Union,  Madison  and  Adams  counties,  thence  southward  into  Taylor. 
Examinations  there,  together  with  those  within  the  county,  leave  no 
doubt  that  the  first  stratified  rocks  beneath  the  drift  -  deposit  in 
Ringgold  are  the  upper  coal  -  measure  limestone ;  the  inference  from 
which  is  that  if  coal  is  ever  obtained  here,  it  will  be  found  at 
considerable  depth  below  the  surface.  It  is  not  at  all  improbable 
that  one  or  more  beds  of  coal  underlie  the  county,  but  if  so,  further 
and  more  extensive  examinations  are  needed  to  give  even  an 
approximate  estimate  of  the  depth  at  which  it  may  be  found. 

The  county  is  so  well  drained  that  hardly  a  single  pool  can  be 
found  within  its  borders,  yet  water  is  abundant  in  the  streams,  and 
also  easily  obtained  at  a  moderate  depth  anywhere  upon  the  high 
lands  except  upon  the  narrow  ridges,  and  immediately  upon  the 
slopes.  The  prairies  are  covered  with  a  luxuriant  growth  of  wild 
grass,  and  the  cultivated  varieties  succeed  admirably.  Consequently 
this  is  destined  to  be  an  important  one  for  stock-raising  as  well  as 
for  purposes  of  general  farming. 

TAYLOR   COUNTY. 

Taylor  county  is  similar  in  the  general  character  of  its  surface  to 
those  which  adjoin  it.  It  has  rather  more  timber  than  Ringgold,  but 
not  so  much  of  either  timber  or  stone  as  Decatur  county.  The 
streams  flow  to  the  southward  through  it  as  in  Ringgold,  but  they 


46 


REPORT  OF  STATE  GEOLOGIST. 


will  not  average  quite  so  large,  and  their  valleys  are  consequently 
not  quite  so  deep  nor  their  slopes  so  abrupt.  The  county  is  per- 
fectly drained  by  its  rivers  and  creeks,  so  that  not  a  marsh  nor  pond 
was  anywhere  seen.  These  streams  afford  good  water  for  stock,  and 
springs  are  not  uncommon  in  depressions  upon  the  prairies.  Excel- 
lent water  is  also  readily  obtained  anywhere  upon  the  prairies  at  a 
very  moderate  depth. 

Timber  enough  for  present  use  can  be  found  in  the  vicinity  of  the 
streams,  which  rapidly  encroaches  upon  the  prairie  where  the  fires 
are  kept  out.  These  trees  also  grow  rapidly  when  planted  upon  the 
prairies.  Hon.  L.  W.  Hillyer,  of  Plattville,  has  some  cottonwood 
trees  about  his  residence  which  he  had  planted  five  years  ago,  and 
which  measure  twenty  -  three  inches  in  circumference  at  the  root. 
His  method  of  propagating  them  is  so  peculiar  and  successful  as  to 
deserve  particular  mention,  and  thorough  trial  by  others.  He 
procured  freshly  cut  poles  of  that  wood  from  the  timber,  chipped 
them  with  an  ax  at  short  intervals,  and  then  planted  them,  end  to 
end  in  shallow  trenches.  Vigorous  sprouts  soon  sprung  from  each 
of  the  chipped  places  which  grew  much  more  rapidly  than  the  young 
trees  which  were  transplanted  with  their  roots  at  the  same  time,  and 
soon  exceeded  them  in  size.  They  have  also  a  much  more  healthy 
and  thrifty  appearance.  Whether  other  trees  may  thus  be  propa- 
gated, remains  to  be  tested.  It  is  very  desirable  that  other  trees, 
particularly  the  White  Maple,  which  grows  vigorously,  should  be 
extensively  propagated,  but  the  cottonwood  grows  more  rapidly  than 
any  other,  and  is  consequently  sooner  available  as  fuel,  although  the 
quality  is  not  so  good  as  that  of  most  others.  Mr.  Hillyer  thinks 
that  if  he  had  planted  ten  acres  in  trees  at  the  time  he  planted  hia 
grove,  he  might  now  have  drawn  all  his  supply  of  fuel  from  that 
source. 

Considerable  portions  of  this  county,  particularly  the  northeastern 
and  southwestern  parts  are  destitute  of  stone.  Several  good 
quarries  are  opened  in  the  upper  coal  -  measure  limestone  on  the  One- 
hundred  •  and- two  river  in  the  vicinity  of  Bedford.  There  are  also 
a  few  exposures  of  the  same  rock  along  the  river  between  Bedford 
and  the  southern  boundary  of  the  State.  In  the  northwestern  part 


REPORT  OF  STATE  GEOLOGIST.  47 

of  the  county,  on  several  points  on  the  East  Nodaway,  above  where 
that  river  enters  Page  county,  a  blue  argillaceous  limestone  is  found, 
and  beneath  it  a  fifteen  -  inch  bed  of  coal  is  being  worked  on  land  of 
Mr.  J.  R.  Foster,  section  29,  township  70,  range  35,  which  is  thus 
far  the  only  bed  of  coal  worked  in  the  county.  It  was  at  first 
believed  that  this  bed  of  coal  belonged  to  the  upper  part  of  the 
lower  coal  -  measures,  but  subsequent  examinations  leave  no  doubt 
that  it  belongs  quite  within  the  upper  series  and  is  believed  to  be  the 
only  bed  which  that  series  contains.  Connected  with  this  change  of 
opinion  is  also  the  belief  that  although  other  beds  of  coal  may  be 
expected  beneath  the  one  now  worked,  they  lie  at  considerable 
depth. 

The  coal  of  Mr.  Foster's  mine  is  of  good  quality,  and  having  a 
large  market  for  it,  he  finds  it  profitable  to  have  it  mined  although 
the  bed  is  so  thin. 

Mr.  Edwin  Houck  is  making  a  good  quality  of  lime  from  his 
quarries  at  Bedford,  for  which  he  finds  a  ready  market,  as  well  as 
for  his  quarry  -  rock. 

The  soil  of  Taylor,  is  of  the  same  excellent  quality  as  that  found 
in  the  counties  before  named. 

The  marketable  products  of  its  citizens  consist  at  present  of  live 
stock,  for  which  buyers  reach  them  from  both  the  eastern  and 
western  borders  of  the  State. 

PAGE  COUNTY. 

Within  the  memory  of  some  now  living  the  growing  wheat  crop  of 
the  Genessee  valley  was  watched  with  lively  interest  by  the  whole 
country,  because  success  or  failure  there  effected  the  market  far 
and  near.  This  was  before  the  Great  West  had  begun  to  send 
forward  for  the  world's  consumption,  her  surplus  store  amounting  to 
millions  of  bushels  of  grain  every  year.  That  vallay,  is  still  fertile 
and  beautiful,  but  now,  in  the  growing  greatness,  of  our  country,  it 
has  dwindled  into  insignificance  compared  with  the  fame  it  once 
possessed.  Other  valleys  have  been  settled  and  cultivated  as  the 
tide  of  civilization  rolled  westward,  which  vie  with  that  in  every- 
thing that  makes  a  region  desirable,  but  being  themselves  in  the 


48  REPORT  OF  STATE  GEOLOGIST. 

inldst  of  boundless  productivenes,  their  excellence  has  become 
known  only  to  the  passing  traveller,  and  to  those  who  dwell  there. 
There  are  yet  others  in  our  Scate  of  surpassing  beauty  and  fertility, 
which  have  only  just  begun  to  be  settled,  and  which  will  in  a  few 
years  produce  more  bread,  and  be  the  seat  of  a  greater  number  of 
happy  homes  than  the  far  famed  valley  of  the  Genessee. 

Page  county  possesses  one  of  these  lovely  regions  in  the  valleys 
of  the  Nodavvays.  These  streams  ought  to  receive  separate  names, 
but  in  the  meagre  nomenclature  of  the  pioneer,  each  large  branch  of 
a  stream  retained  the  name  of  the  principal  one,  with  the  distinctive 
prefix  East,  West,  or  Middle,  as  the  occasion  required.  Thus  we 
have  a  multiplicity  of  Chariton,  Grand,  One  -  hundred  -  and  -  two, 
Nodaway,  Tarkeo  and  Nishnabotony  rivers.  The  West  Nodaway 
stretches  entirely  through  the  county  from  north  to  south,  a  distance 
of  nearty  twenty  -  five  miles,  but  which  is  only  a  small  portion  of  its 
entire  length,  while  the  East  Nodaway  has  a  length  of  only  about 
twelve  miles  in  this  county,  having  entered  it  near  the  middle  of  the 
east  line,  from  Taylor,  which  received  it  in  turn  from  Adams :  but 
more  particular  reference  is  here  made  to  the  West  Nodaway.  The 
character  of  the  approaches  to  this  stream  is  somewhat  different  from 
those  which  drain  the  counties  to  the  eastward  of  it.  The  stream  itself 
lies  about  as  far  below  the  general  prairie  level  as  those  of  similar 
size  in  Taylor  county,  about  one  hundred  and  fifty  feet,  but  the  val- 
ley slopes  are  more  gradual,  commencing  about  a  mile  from  the 
stream  on  either  side.  These  slopes  are  themselves  undulating  like 
the  higher  prairies,  the  drainage  system  of  which  is  here  repeated  in 
miniature.  Shallow,  grassy  ravines  come  down  to  the  stream  at 
intervals,  gradually  diminishing  branches  of  which  extend  outward  on 
either  side  and  up  the  slope,  multiplying  and  draining  the  land  com- 
pletely, and  giving  it  a  very  pleasing  appearance  when  viewed  from 
the  opposite  side.  This  is  the  general  character  of  the  valley  in  its 
whole  extent  through  the  county,  but  yet  it  possesses  diversity 
enough  to  make  it  pleasant  for  the  eye  to  rest  upon  it  at  every  point. 
Although  the  eastern  part  of  Page  county  contains  more  timber  than 
any  other  of  the  southern  tier,  thus  far  seen  west  of  Decatur,  yet 
these  approaches  to  the  Nodaway  are  principally  prairie  slopes,  which 


REPORT  OF  STATE  GEOLOGIST.  49 

allow  their  features  to  be  seen  with  admirable  distinctness.  Imme- 
diately bordering  the  stream,  more  or  less  timber  is  always  found. 
Sometimes,  it  is  true,  it  amounts  to  but  a  very  narrow  belt,  but  at 
other  places  it  is  a  quarter  of  a  mile  or  more  in  width.  Beside  this, 
where  its  tributaries  meet  it,  as  well  as  at  some  other  points  also,  still 
larger  groves  extend  upward  upon  the  slopes;  and  in  the  space 
between  the  East  and  West  Nodaways,  opposite  Clarinda,  there  is  a 
body  of  timber  four  miles  in  width. 

At  this  season  of  the  year  (last  of  July)  the  ripened  heads  of  one 
species  of  prairie  grass  gives  the  surface  a  sere  and  barren  aspect  in 
tha  distance,  and  in  looking  down  upon  this  valley  one  sees  the 
immense  fields  of  green  luxuriant  corn,  and  yellow,  ripened  grain, 
standing  upon  the  surface  like  rectangular  oases  in  a  desert  of  grass. 
This  desert  is  one  only  in  appearance,  for  it  only  needs  the  plow  to 
convert  every  square  rod  of  it  into  fields  fertile  as  those  which  are 
now  there  smiling  with  a  plentiful  harvest. 

The  other  rivers  of  the  county  arc  two  small  streams,  the  East  and 
West  Tarkeo,  both  of  which  traverse  it  from  north  to  south ;  and  the 
East  Nishnabotony,  which  crosses  the  northwest  corner.  A  narrow 
belt  of  timber  skirts  the  latter  river  ;  a  little  is  also  found  on  the 
East  Tarkeo,  but  from  the  latter  stream  to  the  west  line  of  the  coun- 
ty, stretches  one  almost  unbroken,  but  deeply  undulating  prairie,  all 
of  which  is  as  fertile  as  any  soil  in  the  State,  as  occasional  fields  of 
grain  will  testify,  which  are  being  cultivated  wherever  a  grove  of 
trees  forms  the  nucleus  for  a  settlement. 

Limestone  of  good  quality  for  building  purposes  is  quarried  at 
various  points  along  the  East  and  West  Nodaway,  from  Hawleyville 
in  the  east  part  of  the  county,  to  the  Missouri  line ;  a  very  good  sup- 
ply being  obtained  within  a  few  miles  of  Clarinda.  A  persistent 
ledge  of  a  few  layers,  of  a  hard,  ponderous,  bluish  limestone,  two  or 
three  feet  in  thickness,  is  found  cropping  out  at  frequent  intervals  on 
the  prairie  -  points,  and  in  small  streams  bordering  the  East  Tarkeo. 
It  shows  itself  a  little  above  the  level  of  the  narrow  bottom  border- 
ing the  stream,  and  extends  quite  through  the  county  from  north  to 
south,  and  dipping  to  the  southward  at  about  the  same  rate  that  the 
water  falls  in  the  stream,  it  appears  at  about  the  same  elevation 
1 


50  REPORT  OF  STATE  GEOLOGIST. 

above  it  at  all  points.  This  stone  seems  well  adapted  to  all  the  pur- 
poses for  which  stone  is  usually  required,  except  the  manufacture  of 
lime.  Thus  far  efforts  with  it  in  this  direction  have  failed,  although 
it  seems  to  be  composed  principally,  at  least,  of  carbonate  of  lime. 
It  very  much  resembles  in  physical  characters  the  rock  which  has 
been  successfully  used  in  Davis  county  for  the  manufacture  of 
hydraulic  cement. 

The  only  bed  of  coal  yet  found  in  this  county  is  worked  at  various 
points  near  Clarinda,  and  is  identical  with  the  one  which  is  worked 
at  Quincy  in  Adams  county,  and  also  on  Mr.  Foster's  land  in  the 
northwestern  part  of  Taylor  county. 

The  soil  is  everywhere  fertile,  and  almost  everywhere  covered  with 
a  luxuriant  growth  of  grass.  Along  the  valleys  of  the  rivers  of  this 
county,  the  "blue  joint,"  one  ot  the  most  nutritous  of  the  wild  gras- 
ses, is  very  abundant,  making  it  one  of  the  best  natural  stock  -raising 
regions  in  the  world.  Large  numbers  of  cattle,  horses  and  sheep  are 
now  raised  by  the  citizens  of  the  county,  but  thousands  oi  acres  of 
this  excellent  grass  dies  annually,  hardly  a  mouthful  of  which  is  con- 
sumed. The  streams  of  the  county  afford  abundant  water  for  stock, 
and  pure  cold  water  can  be  obtained  at  a  moderate  depth  almost  any- 
where upon  the  prairies,  as  well  as  in  the  valleys.  Bi-sidi;  which, 
excellent  springs  are  not  unfrequently  found  along  the  slopes  of  the 
streams. 

FREMONT  COUNTY. 

This  county  is  more  distinctly  marked  in  its  surface  features 
than  any  of  those  between  it  and  the  Des  Moines  HUT,  which 
difference  is  due  to  two  distinct  causes  not  possessed  by  smy  of  those. 
The  first  of  these  causes  is  the  great  Missouri  river  whirls  courses 
along  its  western  border,  and  which,  aside  from  the  effer  -  produced 
in  its  own  immediate  vicinity,  has  also  had  a  modifying  influence  upon 
the  drainage  of  the  county  by  the  Nishna,botany  and  its  tributaries. 
The  second  cause  is  the  existence  over  a  great  part  of  tl  rounty  of 
a  peculiar  deposit  which  forms  the  soil  where  it  exists,  as  well  as 
much  of  the  material  beneath  it,  all  resting  upon  the  drii  iho  finely 
pulverized  upper  portion  of  which  forms  the  soil  in  other  ;  rtions  of 
the  State. 


REPORT  OF  STATE  GEOLOGIST.  51 

This  deposit  has  been  called  by  Prof.  Swallow,  State  Geologist  of 
Missouri,  "  the  bluff  deposit, "  which  term  will  also  be  used  in  these 
communications  from  the  field.  It  is  composed  of  very  finely 
comminuted  silicious  matter,  with  much  clayey  and  limy  material,  a 
part  of  the  latter  having  formed  into  stony  concretions,  from  the 
size  of  a  nut  to  a  forty  pound  shot.  With  the  exception  of  these 
concretions,  which  form  a  very  inconsiderable  part  of  it,  the  whole 
mass  is  very  uniform  in  its  color  and  composition  from  top  to 
bottom,  even  where  it  is  more  than  two  feet  thick.  It  is  of  a 
slightly  yellowish  ash  color  where  it  has  not  been  rendered  darker 
by  decomposed  vegetable  matter  resulting  from  the  profusion  of 
grasses  and  plants,  which  grow  upon  it  in  every  favorable  situation. 

Resting  upon  the  drift,  which  it  will  be  remembered  contains  the 
water  -  worn  pebbles,  boulders  and  sand,  it  has  of  course  been  formed 
at  a  subsequent  period,  and  bears  within  itself  the  evidences  of  its 
origin  in  a  fresh  water  lake  which  was  doubtless  anciently  an 
expansion  of  the  Missouri  river.  * 

There  is  reason  to  believe  that  this  deposit  does  not  extend 
eastward  of  the  Nishnabotanys  in  Fremont  county,  but  its  exact 
limit  in  this  direction  is  not  clearly  defined,  from  the  fact  that  the 
fine  material  of  the  upper  portion  of  the  drift  forms  a  soil  almost 
identical  in  appearance  in  most  places,  with  that  formed  by  the  bluff 
deposit,  supporting  the  same  profusion  of  grasses  and  plants,  and 
presenting  but  little  to  the  eye  of  the  casual  observer  to  indicate  a 
change  of  composition  in  the  soil  -  material.  It  is  along  the  border 
of  the  Missouri  river  bottom,  and  in  excavations  such  as  cellars  and 
wells,  that  the  strange  peculiarities  of  this  deposit  are  seen.  Exca- 
vations are  made  in  it  with  less  labor  than  in  the  drift,  and  when 
moist  a  strong  man  can  thrust  a  spade  into  it  without  difficulty.  Yet 
wells  dug  in  it  and  walled  only  just  above  the  water  line,  remain 
unchanged  for  years,  the  sides  showing  the  spade  marks  upon  them 
as  when  they  were  first  dug.  Very  good  cellars  are  also  made  in  it, 
the  perpendicular  banks  of  which  remain  without  a  wall  or  other 
support,  and  sometimes  even  the  steps  are  carved  out  of  it,  which 
when  dry,  as  it  usually  becomes,  remain  serviceable  for  a  long  time 
with  a  little  care. 


*  See  the  article  entitled  "Lakes  of  Iowa,  Past  and  Present,  "  on  another  page. 


52  REPORT  OF  STATE  GEOLOGIST.. 

Bordering  the  Missouri  river  bottom — which,  with  the  exception 
of  a  narrow  belt  of  timber  along  the  river,  is  in  this  county  a  nearly 
level  prairie  from  three  to  six  miles  wide  —  the  bluff  deposit  ends  as 
abruptly  as  the  rocky  cliffs  of  the  Mississippi,  and  viewing  the 
fantastic  shapes  into  which  it  has  been  carved  by  fiuvatile  and 
meteorological  erosion,  one  can  hardly  rid  himself  of  the  idea  that 
these  too,  are  supported  by  a  frame  -  work  of  rock.  But  this  is  not 
the  case,  for  not  a  stone  of  any  kind  is  to  be  found  in  the  whole 
mass  save  the  limy  concretions  above  referred  to.  Along  the  base  of 
these  bluffs  between  the  northern  and  southern  line  of  the  county, 
ledges  of  the  upper  coal  -  measure  limestone  and  sandstone  are  found, 
resting  upon  which  a  comparatively  thin  deposit  of  drift  is  seen 
with  its  boulders,  gravel  and  sand,  which  in  turn  bears  upon  itself 
the  bluff  deposit.  This  towers  up  above  the  drift  in  some  places 
more  than  two  hundred  feet,  and  upward  of  two  hundred  and  fifty 
feet  above  the  general  level  of  the  river  bottom. 

Frequent  springs  of  pure  oold  water  issue  from  the  drift  at  the 
base  of  the  bluff  deposit,  and  there  are  also  evidences  of  the  former 
existence  of  many  which  have  ceased  to  flow  or  that  have  sought 
other  channels.  These  springs  have  doubtless  had  some  effect  in 
producing  the  peculiar  outline  which  the  face  of  the  bluff  presents, 
particularly  in  forming  the  beautiful  little  natural  ampitheaters, 
containing  from  a  few  square  rods  to  an  acre,  covered  with  box  -  elder 
and  other  trees,  opening  toward  the  river,  but  nearly  surrounded 
by  high  buttresses  and  undulating  precipitous  slopes  which  are 
covered  sparsely  with  prairie  grass  to  their  tops.  From  some  of 
these,  springs  still  issue,  making  them  delightful  nooks  in  which  to 
hold  pic  - nics,  or  for  the  matter-of-fact  farmer  to  shelter  his  stock. 
In  many  places  the  bluffs  are  so'  precipitous  that  they  appear  almost 
perpendicular,  but  this  is  far  from  being  the  case,  since  appearances 
of  this  kind  are  always  deceptive.  The  steepest  fronts  will  average 
less  than  an  angle  of  forty -five  degrees  with  the  hojizon,  and  the 
boldest  and  most  precipitous  one  we  found,  upon  which  the  grass 
was  growing,  when  tested  with  the  clinometer  proved  to  be  only  fifty 
degrees.  There  are  occasional  places  in  some  of  the  more  promi- 
nent fronts  where  the  material  has  fallen  down,  which  present  bared 
faces  for  a  short  distance,  which  are  in  reality  nearly  perpendicular, 


REPORT  OF  STATE  GEOLOGIST.  53 

and  these  stand  there  year  after  year,  with  little  or  no  change, 
becoming  so  dry  that  no  grass  can  grow  upon  them,  and  giving  the 
appearance  in  the  distance  of  a  rocky  cliff.  There  is  a  peculiar 
rounding  to  the  summits  of  these  bluffs  many  of  which  resemble  the 
artificial  mouni  raised  by  a  departed  race  of  Indians  upon  those 
which  border  the  Mississippi,  but  their  great  number  would  undeceive 
one  in  this  respect  if  their  shapes  were  not  more  varied,  and  their 
ridges  and  slopes  also  did  not  partake  of  the  same  character. 
Being  destitute  of  trees  upon  their  summits,  and  stretching  north- 
ward and  southward  so  far  as  the  eye  can  reach,  they  present  a 
strange  and  impressive  aspect  quite  different  from  that  produced  by 
any  other  formation  in  the  State. 

Proceeding  inland  from  the  great  river,  the  surface  becomes  much 
less  broken  although  the  material  is  the  same,  and  a  great  portion 
of  that  which  is  not  occupied  by  fertile  farms,  is  covered  by  a 
thrifty  growth  of  timber;  and  approaching  this  county  from  the 
prairies  which  lie  to  the  eastward  of  it,  one  sees  for  the  first  time 
since  leaving  Decatur  county,  the  horizon  serrated  with  forest  trees 
growing  upon  the  high  lands  and  slopes. 

The  Missouri  river  bottom  is,  in  this  county  at  least,  somewhat 
different  in  character  from  that  of  the  Mississippi.  Here  are  none 
of  the  definite  terraces  which  are  often  seen  there,  and  the  whole  is 
more  nearly  level  from  the  river  to  the  bluff.  The  greater  part  of  it 
is  prairie,  and  much  of  it  is  never  reached  by  the  highest  floods  of 
the  river,  perhaps  excepting  those  which  occur  at  intervals  of  many 
years.  The  soil  here  is  of  the  most  extraordinary  fertility.  Wells 
dug  in  it  show  a  depth  of  more  than  ten  feet,  every  inch  of  which  is 
as  fertile  as  that  turned  by  the  plow.  There  are  some  farms  upon 
this  bottom  which  have  yielded  a  bountiful  crop  of  corn  every  year 
for  fifteen  years,  without  rotation  of  crops,  without  manure,  and 
almost  without  care.  The  formation  of  this  bottom  land  was  long 
subsequent  to  that  of  the  bluff  deposit,  from  which  much  of  its 
material  was  derived,  which,  as  already  explained,  was  deposited  at 
a  period  subsequent  to  that  in  which  the  drift  with  its  own  product- 
ive soil  was  formed.-  Thus  we  perceive  that  this  county  presents 
excellent,  and,  indeed,  remarkable  examples  of  soil  of  diluvial, 


54  REPORT  OF  STATE  GEOLOGIST. 

lacustrine,  and  fluvatile  origin,  each  succeeding  the  other  in  order 
of  time  ;  all  of  which  are  also  of  remarkable  fertility. 

The  northeastern  and  southeastern  portions  of  Fremont  county 
are  nearly  all  prairie,  but  the  region  along  the  Nishnabotany  and  its 
tributaries,  as  well  as  a  great  part  of  the  county  west  of  that  river, 
furnishes  much  more  than  the  average  amount  of  timber.  In  the 
description  of  Page  county,  considerable  space  w;;s  devoted  to  a 
description  of  the  valley  of  the  Nodaway,  but  the  great  length  of 
this  letter  makes  it  necessary  to  close  it  vithout  doing  full  justice  to 
the  valleys  of  the  Nishnabotany  and  its  tributaries.  A  few  words, 
however,  must  be  said  concerning  its  general  features,  and  these  will 
be  confined  to  the  West  river,  which  extends  from  the  northern  to 
the  southern  line  of  the  county,  almost  directly  through  its  middle. 
It  is  a  larger  stream  than  the  Nodaway,  and  its  valley  occupies  a 
much  wider  area,  but  nearly  all  that  was  said  of  that  valley  is  also 
applicable  to  this.  The  approaches  to  the  stream,  however,  are 
longer  and  more  gradual;  the  valley  is  wider  from  the  highest  land 
on  either  side,  averaging  four  miles  or  more  in  width,  and  then  it  has 
also  a  distinct  bottom,  which  is  not  so  marked  a  feature  of  that  of 
the  Nodaway. 

A  dweller  by  the  Mississippi,  viewing  this  valley  from  the  high 
lands  for  the  first  time,  would  be  likely  to  mistake  the  real  character 
of  its  bottom,  for  it  is  not  in  reality  so  flat  as  those  he  is  accustomed 
to  see  there.  Far  the  greater  portion  of  it  is  never  reached  by  the 
highest  floods  which  swell  the  river  in  wet  seasons.  Standing  near 
the  river,  and  looking  toward  the  slopes  on  each  side,  the  bottom  land 
will,  in  most  cases,  be  seen  to  rise  without  a  terrace  towards  them,  at 
the  rate  of  about  forty  feet  in  the  mile,  the  distance  from  the  foot  of 
the  slope  to  the  river  being  often  as  much  or  more  than  this.  There 
are  occasional  low  places  which  are  reached  by  the  high  waters,  but 
most  of  them  are  drained  when  the  waters  subside,  leaving  no  pond, 
and  the  surface  becomes  covered  with  grass  every  year.  The  soil  of 
these  places,  and  that  closely  bordering  the  stream  is  composed  of 
the  disturbed  material  of  the  bluff  deposit,  while  the  higher  portions 
of  the  bottom  land  are  composed  of  unaltered  bluff  material  like  the 
high  lands  along  the  border  of  the  valley  and  to  the  westward  of  it. 
The  view  of  this  valley  from  the  high  lands  is  everywhere  so  delightful 


REPORT  OF  STATE  GEOLOGIST.  55 

that  it  is  not  easy  to  select  any  one  region  which  greatly  excels 
another  in  this  respect,  but  no  person  capable  of  appreciating  the 
beautiful  can  pass  over  the  road  from  Sidney  to  Hamburg  without 
being  thankful  that  his  eyes  were  permitted  to  rest  upon  scenes  so 
lovely  as  those  which  meet  his  view  all  the  way. 

The  deep  drift  in  the  eastern  part  of  the  county,  and  the  deeper 
bluff  deposit  of  the  middle  and  western  portions  have  covered  from 
sight  all,  or  nearly  all  the  stratified  rocks  which  exist  beneath  it, 
except  along  the  base  of  the  Missouri  river  bluffs,  the  most  southern 
exposure  of  which  is  seen  on  the  town  lot  of  Mr.  Allen  near  his 
saw  -  mill  in  Hamburg.  This  is  now  nearly  obscured  by  grading,  but 
enough  was  seen  to  indicate  several  layeis  of  upper  coal -measure 
limestone  with  marly  partings,  resting  upon  a  fine  grained,  micaceous 
sandstone,  at  an  elevation  of  thirty  or  forty  feet  above  the  general 
level  of  the  river  bottom.  Following  up  the  base  of  the  bluff  along 
the  bottom  road  to  Plum  Creek  the  exposures,  particularly  of  the 
limestone,  become  more  frequent,  and  afford  good  quarry  -  rock.  At 
about  two  miles  above  Plum  creek,  and  extending  thence  some  two 
miles  further  along  the  base  of  the  bluffs,  there  are  very  full 
exposures  of  limestone,  which  afford  the  finest  and  most  extensive 
quarries  yet  seen  west  of  Madison  county.  The  stone  closely 
resembles  those  obtained  from  the  quarries  of  that  county,  in  quality 
as  well  as  in  the  excellence  of  its  lime.  It  can  be  obtained  here 
in  almost  any  desired  quantity,  and  with  not  greater  than  the 
ordinary  amount  of  labor  in  quarrying. 

Near  the  residence  of  Mr.  John  Wilson,  on  Section  14,  township 
70,  range  43,  this  gentleman  kindly  pointed  out  a  place  where  a  ten 
inch  bed  of  coal  has  been  exposed  by  excavation  ;  an  examination 
of  which,  together  with  the  strata  above  and  below  it,  leaves 
but  little,  if  any  doubt,  that  it  is  a  continuation  of  the  same  bed 
which  is  being  worked  in  Adams,  Taylor  and  Page  counties.  It  is 
hardly  probable  that  this  bed  will  be  found  thick  enough  to  be  prof- 
itably worked  in  this  county. 

The  brick  made  in  this  county  are  of  very  fair  quality,  the  clay 
for  which  was  obtained  from  the  drift,  at  the  base  of  the  bluff 
deposit,  at  the  only  yard  where  it  was  examined.  The  bluff 
material  would  itself  probably  make  very  fair  brick  were  it  not 


56  REPORT  OF  STATE  GEOLOGIST. 

that  the  small  limy  concretions  which  it  contains,  are  changed  to 
to  quick  -  lime  when  the  bricks  are  burned,  and  then  when  exposed 
to  moisture  the  slaking  of  the  lime  bursts  them. 

MILLS  COUNTY. 

The  counties  of  Mills  and  Fremont  are  so  similar  in  geological 
character,  as  well  as  in  those  topographical  features  which 
distinguish  them  from  the  counties  lying  to  the  eastward  of  them 
that  much  of  the  description  of  one  would  be  equally  applicable 
to  the  other.  In  view  of  this,  and  of  the  unusual  length  of  rny 
letter  on  Fremont  county,  some  of  the  topics  discussed  therein  will 
be  continued  in  this,  and  others  will  now  receive  attention  which 
were  omitted  in  that. 

Although  Mills  county  seems  to  contain  proportionally  a  little 
less  timber  than  Fremont,  yet  it  has  more  than  the  counties  east- 
ward of  those  on  the  Missouri  watershed  will  average;  the  principal 
portion  of  which  is  found  in  the  western  half  of  the  county. 
Wherever  the  fires  are  kept  from  the  prairies  the  young  timber 
grows  up  with  great  rapidity,  so  that  one  frequently  sees  considera- 
ble bodies  of  forest  trees  of  the  various  kinds  common  to  the  State, 
large  enough  to  use  for  fuel,  which  have  grown  up  since  the  country 
was  settled.  These  trees,  as  well  as  the  osage  orange  also,  succeed 
well  when  planted  upon  the  prairies  that  rest  upon  the  bluff  deposit, 
as  well  as  those  which  rest  upon  the  drift. 

The  beautiful  and  fertile  valley  of  the  .Nishnabotany  extends 
through  the  county  from  north  to  south,  and  is  almost  identical  in 
character  with  that  part  of  it  lying  in  Fremont,  and  the  smaller  but 
no  less  beautiful  valleys  of  Silver  and  Keg  creeks  traverse  large 
portions  of  the  northern  and  central  parts.  These  valleys  with 
their  tributary  depressions  are  not  as  deep  as  the  valleys  of  similar 
streams  are  in  some  of  the  counties  to  the  eastward  and  the 
approaches  to  them  are  so  gentle  that  they  can  all  be  as  easily 
cultivated  as  the  more  level  land.  This  character  of  the  valleys 
began  to  be  distinctly  perceptible  upon  reaching  the  Nodaway,  and 
at  the  same  time,  that  clearly  defind  ocean -like  horizon  of  the 
prairie  level  observed  in  Wayne  and  elsewhere  began  to  be  less 
distinct,  and  these  changes,  particularly  the  former,  are  more  readily 


REPORT  OF  STATE  GEOLOGIST.  57 

recognized,  as  one  passes  westward  into  Fremont  and  Mills  counties; 
the  nearest  approach  to  a  definite  prairie  horizon  being  seen  in 
the  northern  part  of  Mills.  The  eastern  border  of  the  bluif  deposit 
was  not  recognized  in  this  county,  and  it  doubtless  extends  over  the 
whole  surface,  except  where  the  streams  have  eroded  their  valleys 
through  it,  reaching  the  drift  with  its  gravel  sand  and  boulders 
beneath,  but  by  this  means  it  was  seen  to  be  much  thinner  in  the 
western  part  of  the  county. 

The  Missouri  river  bottom  extends  the  full  length  of  the  county 
as  in  Fremont,  the  character  of  it  being  similar,  and  the  width 
averaging  about  the  same,  for  the  river  nowhere  approaches  the 
bluffs  in  either  of  these  counties.  The  bluffs  of  Mills,  generally 
slope  more  gradually  to  the  bottom  lands,  and  are  more  frequently 
wooded  than  in  Fremont ;  and  where  the  timber  does  not  exist  the 
slopes  are  more  thickly  covered  with  grass.  This  results,  not  from 
any  change  in  the  character  of  the  material,  but  wholly  in  conse- 
quence of  the  more  gradual  sloping  of  the  hills,  thus  retaining  the 
moisture  ;  for  where  the  peculiar  material  of  which  they  are  formed 
is  exposed  in  such  prominent  and  precipitous  masses  as  are  some- 
times seen,  it  becomes  too  dry  to  support  vegetation  ;  yet  under  more 
favorable  circumstances  every  part  of  it,  even  when  thrown  out  of 
deep  wells,  produces  a  luxuriant  growth,  both  of  plants  and  trees. 
Thus  many  of  the  bluffs  of  Mills  county  are  wooded  upon  their 
slopes,  while  their  prominent,  rounded  summits  are  destitute  of  trees, 
reminding  us  of  the  waning  locks  of  our  honored  sires. 

The  material  composing  the  bluff- deposit  has  some  physical  char- 
acteristic which  are  very  remarkable.  One  of  the  most  striking  of 
which  is  the  constancy  with  which  it  remains  unchanged  b'y  atmos- 
phere or  frost,  in  any  shape  which  has  been  given  to  it  by  natural 
or  artificial  forces,  while  it  can  be  readily  excavated  by  the  spade 
alone.  It  is  this  which  maintains  the  bluffs  in  their  strange  and 
peculiar  shapes  as  unchanged  in  form  as  those  are  in  other  parts 
of  the  country  which  are  supported  by  a  framework  of  rocks. 
Wells  dug  in  it  do  not  need  walls  above  the  water  line ;  stock 
shelters  dug  in  the  hillsides  are  serviceable  for  many  years ; 
roads  upon  it  become  hard  and  do  not  wash  easily  by  the  rains. 


58  REPORT  OF  STATE  GEOLOGIST. 

and  thus  the  roads  of  this  region  are  among  the  best  in  the 
State,  for  there  is  not  a  stone  to  jar  the  wheels,  nor  deep  ruts  to 
impede  them.  It  dries  so  readily  that  lime  and  pottery  kilns  are 
dug  out  in  the  prominent  points,  and  used  as  well  and  as  long 
without  walls,  as  they  can  be  with  them  in  other  places.  And  yet 
the  soil  formed  from  the  same  material  will  endure  a  drouth  as  well 
as  any  other,  and  those  who  till  it  claim  that  it  is  better  than  the 
average  in  this  respect.  The  water  of  springs  and  creeks  run 
perfectly  clear  upon  it  much  of  the  time,  and  where  they  have  finally 
cut  their  narrow  channels  down,  the  banks  remain  precipitous  and 
the  ravines  very  short  beyond  the  issuance  of  the  spring. 

All  that  was  said  of  the  excellence  of  the  soil  of  Fremont  county 
is  also  applicable  to  that  of  Mills,  and  the  stratified  rocks  of  both 
counties  bear  the  same  relation  to  the  productive  coal  -  beds  of  the 
Des  Moines  River  Valley.  Large  quantities  of  excellent  limestone 
are  found  along  the  base  of  the  bluifs  in  the  southwestern  part  of 
the  county.  The  exposures  are  almost  identical  in  character  with 
those  in  the  northwestern  part  of  Fremont,  and  the  quality  of  the 
rock,  aboiit  the  same.  A  couple  of  quarries  of  limestone  also  exist 
on  Silver  Creek,  in  the  south  part  of  the  county,  and  in  the  north- 
eastern corner,  there  are  considerable  exposure  of  sandstone,  some 
of  which  is  quarried  by  Mr.  Peter  Cooper,  and  wrought  into  various 
shapes  for  building  purposes. 

Some  of  the  layers  of  limestone  both  in  Mills  and  Fremont 
counties,  closely  resemble,  in  physical  characters,  a  stone  which  has 
been  successfully  used  in  Davis  county  for  the  preparation  of 
hydraulic  cement.  Even  if  these  should  be  found  upon  trial  to 
produce  a  good  quality  of  that  valuable  article,  any  person  contem- 
plating the  manufacture  of  it,  should  satisfy  himself  of  the  existence 
of  a  large  and  constant  supply  of  the  stone,  and  also  that  its 
character  is  uniform  ;  for  that  of  the  various  localities  which  famish 
the  best  cement,  is  almost  never  identical  in  composition,  and  some- 
times they  are  widely  different  in  this  respect,  while  furnishing 
equally  good  cement.  It  thus  becomes  necessary  that  the  stone  of 
each  locality  should  be  studied  and  experimented  with  independently 
of  others. 

At  various  points  along  the  base  of  the  bluffs,  both  in  Mills  and 


REPORT  OF  STATE  GEOLOGIST.  59 

Fremont  counties,  where  springs  issue  or  have  issued  in  former 
times,  considerable  masses  of  porous  stone  are  seen,  which  are 
always  of  limited  extent,  and  have  been  formed  entirely  by  the 
spring  water  giving  up  a  portion  of  its  lime  upon  coming  in  contact 
with  the  atmosphere.  This  is  found  in  various  parts  of  the  world, 
and  is  called  calcareous  tufa.  Another  curious  fact  observed  there  is  the 
formation  of  small  masses  of  sandstone  by  the  same  natural  process, 
the  lime  from  the  water  forming  a  cement  as  it  has  percolated  through 
the  sand  often  found  in  the  drift,  at  the  base  of  the  bluffs.  At  a 
point  not  far  from  St.  Mary's,,  in  Mills  county,  a  mass  of  natural 
"  concrete  "  was  found,  formed  in  the  same  manner.  This  mass  was 
identical  in  appearance  with  that  used  in  the  construction  of  "  con- 
crete houses,  "  so  much  recommended  a  few  years  ago.  The  granite 
and  greenstone  pebbles  it  contained,  prove  it  to  have  been  derived 
from  the  drift.  But  these  substances  are  merely  curious,  and  not  of 
any  economic  value,  and  are  only  mentioned  here  to  correct  the 
impression  that  they  are  parts  of  large  masses  of  stone  extending 
beneath  the  surface. 

The  brick  manufactured  in  Mills  county,  are  very  good,  far  better 
than  any  seen  in  the  prairie  region  lately  passed  over.  The  material 
from  which  they  are  made  at  Glenwood,  is  taken  from  the  base 
of  the  bluff  deposit,  four  or  five  feet  of  which,  at  the  base,  contains 
more  clay  than  that  above.  It  is  the  practice  there  to  mix  the  whole 
together,  since  they  find  that  the  upper  portion  has  not  coherence 
enough  to  hold  the  bricks  together  while  drying,  and  the  lower 
portion  cracks  by  the  same  process. 

POTTAWATTAMIE  COUNTY. 

The  great  thoroughfares  of  the  earth,  around  which  wealth  and 
civilization  cluster,  and  along  which  property  is  always  most  valuable, 
are  not  arbitrarily  located  by  man,  but  their  routes  are  in  a  great 
measure  determined  by  geological  features,  themselves  the  result  of 
geological  causes  which  completed  their  operations  long  before  he 
was  created.  It  is  from  such  causes  as  these  that  the  continents 
have  their  outline,  mountains  range  their  elevation,  the  sea  its 
bounds,  and  the  rivers  their  volume  and  direction ;  and  now,  while 
the  rapid  tide  of  civilization  is  setting  across  the  continent,  requiring 


go  REPORT  OF  STATE  GEOLOGIST. 

the  establishment  of  new  and  more  artificial  lines  of  intercommu- 
nication, similar  circumstances,  resulting  also  from  the  operations  of 
nature  herself,  and  therefore  immutable,  are  rapidly  making  Potta- 
wattamie  county  one  of  the  most  important,  as  it  is  in  superficial 
area  one  of  the  largest  counties  in  the  State.  The  great  Missouri 
river  which  flows  along  its  western  border  will  never  cease  to  bear 
the  burthens  of  its  commerce,  but  the  commercial  importance  of 
the  river  to  this  county  is  much  diminished  by  the  fact  that  the 
latter  lies  directly  in  the  course  of  one  of  the  great  lines  of  railway 
which  are  soon  to  connect  the  Atlantic  with  the  Pacific  ocean ;  and 
the  further  fact  that  natural  causes  will  tend  to  converge  some  of 
the  proposed  Iowa  lines  of  railway  to  a  point  within  it,  and  near  the 
Missouri  river.  The  principal  of  these  natural  causes  —  and  none 
other  will  be  discussed  —  consists  in  the  peculiar  and  deep  erosion 
of  the  valleys  of  the  larger  tributaries  of  the  Missouri  river  which 
have  their  confluence  with  it  to  the  northward,  which  render  it  nearly 
impracticable  to  build  the  proposed  east  and  west  lines  directly 
across  them.  Upon  reaching  these  from  the  eastward,  they  must 
bend  their  course  southward  along  the  valleys  of  these  streams  in 
order  to  reach  the  Missouri  river  with  facility,  or  to  connect  with 
the  great  Paciffc  railway  opposite  Council  Bluffs.  These  circum- 
stances will  probably  require  them  all,  either  to  pass  into  this 
county,  or  to  approach  it  so  nearly  as  to  render  a  connection  with 
those  within  it  desirable. 

These  advantages,  although  remote  in  their  origin  aud  indirect  in 
their  characters,  are  of  immense  importance,  and  would  in  time  cause 
an  unfruitful  land  to  be  desirable,  but  in  addition  to  these,  Potta- 
wattamie  county  has  fully  an  average  of  inherent  natural  advan- 
tages, not  the  least  of  which  is  the  possession  of  more  than  half  a 
million  acres  of  as  fertile  and  tillable  soil  as  can  be  found  in  the 
State. 

That  of  the  higher  lands  is  composed  almost  entirely  of  the  bluff 
deposit,  which  extends  nearly  or  quite  to  the  east  line  of  the  county. 
The  greater  part  of  its  surface  is  prairie,  the  grasses  of  which  are  of 
the  more  nutritious  varieties,  rendering  it  one  of  the  most  desirable 
grazing  regions  to  be  found.  The  beautiful  valley  of  the  West 
Nishnabotany  passes  through  its  eastern  portion  from  north  to  south, 


REPORT  OF  STATE  GEOLOGIST.  Q1 

which  is  also  the  general  direction  of  all  the  other  streams  that  drain 
the  county.  This  is  done  so  completely  that  hardly  a  pool  of 
stagnant  water  can  be  found  within  its  borders ;  yet  the  smallest 
of  the  streams,  even  in  the  present  dry  season,  afford  an  abundance 
of  water  for  stock.  Excellent  wells  can  be  obtained  almost  every- 
where, except  in  the  immediate  vicinity  of  the  bluffs,  and  springs  of 
pure  cold  water  are  aften  found  along  the  banks  of  the  streams, 
although  often  no  stone  or  tree  is  near  them  to  mark  the  spot. 

Wood  is  more  abundant  in  the  western  than  in  other  parts  of  the 
county,  where  large  bodies  of  young  timber  are  rapidly  growing  up. 

Limestone  of  good  quality  for  lime,  and  also  for  building  pur- 
poses is  found  in  township  74,  range  40,  and  large  quarries  of  excel- 
lent limestone  are  found  three  miles  eastward,  and  also  six  miles 
northward  from  Council  Bluffs. 

At  various  places  along  the  base  of  the  bluffs  bordering  the 
Missouri  River  bottom,  large  masses  of  coarse  sandstone  and  con- 
glomerate, as  well  as  of  light  porous  limestone  are  frequently  seen, 
which  appear  in  some  cases  to  be  parts  of  regular  ledges  of  rock, 
but  which  are  in  reality  of  only  limited  extent,  and  have  been 
formed  by  the  deposition  of  lime  from  the  spring  water  which  issues, 
or  has  issued  near  them.  The  porous  limestone  has  been  formed 
wholly  from  the  limy  material  deposited  from  the  water  upon 
reaching  the  atmosphere,  and  although  impure,  a  similar  substance 
has  been  used  to  make  lime  in  some  parts  of  the  country,  in  the 
absence  of  better  material.  The  sandstone  arid  conglomerate  have 
been  formed  by  the  percolation  of  the  limy  water  through  the  beds 
of  sand  and  pebbles  belonging  to  the  drift,  cementing  their  particles 
together  while  they  remained  in  the  exact  position  in  which  they 
were  deposited.  Thus  when  these  beds  of  loose  material  were 
deposited  in  horizontal  layers,  they  retained  that  position  when  con- 
solidated, and  now  present  the  appearance  somewhat  of  rocky  ledges. 
Some  of  these  masses  are  quite  hard,  but  the  cementing  material 
being  merely  a  carbonate  of  lime,  they  are  probably  not  so  strong 
as  the  same  mass  would  in  time  become  if  prepared  with  quicklime ; 
for  in  that  case,  a  part  at  least  of  the  cement  would  be  a  silicate  of 
lime,  which  is  stronger  and  more  indestructible. 


62  REPORT  OF  STATE  GEOLOGIST. 

The  question  is  often  asked  by  the  people,  "do  stones  grow?"  or 
in  other  words,  "are  they  now  in  process  of  formation  by  increase?" 
The  reply  is  almost  invariably  in  the  negative,  for  the  question  is 
usually  asked  in  relation  to  the  stones  as  we  usually  see  them,  which 
not  only  do  not  grow,  but  like  everything  else  without  life  have  a 
constant  tendency  to  disintegration  and  destruction.  Some  rocks, 
such  as  some  of  our  boulders,  are  believed  to  have  had  their  origin 
as  such  by  fire  when  the  foundations  of  the  earth  were  laid,  or  by 
subsequent  fusion,  but  all  the  strata  of  rock  in  OUK  State  at  least, 
had  their  origin  at  the  bottom  of  the  sea,  ages  subsequent  to  the 
formation  of  most  of  the  granite  rocks,  from  which  the  majority  of 
our  boulders  are  derived.  The  sea  of  course  then  covered  the 
ground  where  we  find  them,  and  similar  strata  are  doubtless  now 
being  formed  beneath  the  sea,  but  human  eyes  can  never  actually 
witness  the  operation.  These  masses  are,  however,  an  exception  to 
the  rule,  and  are  now  actually  in  process  of  formation  beneath  our 
eyes.  None  of  these  adventitious  rocks  are  of  any  considerable 
value,  but  are  yet  very  interesting  to  those  who  are  fond  of  studying 
the  operations  of  nature. 

These  springs,  although  containing  so  much  lime,  are  nevertheless 
quite  wholesome,  and  some  of  them,  two  or  three  miles  above  Council 
Bluffs,  are  among  the  largest  in  the  State,  the  waters  of  which,  if 
collected,  might  probably  supply  the  city  until  the  increasing  popu- 
lation should  render  them  inadequate  for  that  purpose. 

The  peculiar  bluffs  mentioned  as  so  striking  a  feature  in  Fremont 
and  Mills  counties  also  extend  all  the  way  through  Pottawattamie 
county,  bordering  the  broad  river  bottom.  The  extraordinary  deposit 
of  which  these  bluffs  are  formed  reaches  its  typical  development  in 
Pottawattamie,  and  a  point  near  Council  Bluffs  was  selected  by  Dr. 
Owen  from  which  to  prepare  an  engraved  view  of  the  bluffs  which 
embellishes  his  geological  report  to  the  General  Government. 

Faint  traces  of  glacial  action  were  observed  upon  the  upper  layers 
of  limestone  in  the  quarry  now  worked  by  Mr.  Merritt,  six  miles 
north  of  Council  Bluffs,  but  they  are  not  so  distinct  as  those  seen 
in  Mills  county,  and  also  a  mile  south  of  Omaha,  all  of  which  are 
described  on  other  pages. 


REPORT  OF  STATE  GEOLOGIST.  53 

Very  little  can  yet  be  said  in  reply  to  the  great  questions  constant- 
ly asked  by  the  people,  "  Have  we  any  coal  or  other  valuable  mate- 
rial beneath  our  fertile  soil  ?  "  The  probability  of  finding  any  other 
valuable  mineral  substance  besides  coal  in  this  county  is  so  slight 
that  little  or  no  especial  attention  is  given  to  that  branch  of  investi- 
gation ;  and  all  that  can  now  be  said  upon  the  subject  of  coal  in  addi- 
tion to  what  has  been  said  in  the  introductory  pages,  is  that  it  is  bare- 
ly possible  that  the  bed  now  worked  along  the  Nodaway  may  be 
found  in  the  western  part  of  Pottawattomie  county ;  but  if  found  it 
will  doubtless  be  thin  and  of  little  value. 

MONTGOMERY  COUNTY. 

Montgomery  partakes  of  the  character  of  both  Page  and  Mills 
counties,  which  it  adjoins,  which  have  been  before  described.  Apart 
of  its  soil  is  composed  of  the  bluff  deposit,  and  a  part  of  it  of  the  fine 
material  of  the  drift.  The  division  between  these  two  varieties,  seems 
to  be  along  the  valley  of  the  Nishnabotany.  Yet  this  is  always  dif- 
ficult to  determine  from  appearance  alone,  and  in  this  county  at  least, 
the  soil  is  equally  fertile  in  most  cases.  All  that  has  been  said  of 
the  valley  of  the  Nodaway  in  Page  county,  and  that  of  the  Nishna- 
botany in  Mills  and  Fremont  is,  to  a  great  extent,  applicable  to  Mont- 
gomery ;  for  both  of  these  beautiful  valleys  extend  entirely  through 
the  county  from  north  to  south.  It  is  well  drained  throughout  its 
entire  extent,  like  all  the  region  round  about  it.  It  is  well  watered 
also  by  its  streams,  and  along  the  larger  ones  a  considerable  amount 
of  timber  is  found,  the  young  growth  of  which  rapidly  encroaches 
upon  the  prairies  that  are  not  annually  burned.  Pure,  wholesome 
water  is  obtained  without  difficulty  at  a  moderate  depth  almost  any- 
where upon  the  high  lands  and  in  the  valleys. 

Limestone  is  found  in  considerable  quantity  at  various  points  along 
the  Nishnabotany  in  townships  seventy  -  two  and  seventy  -  three,  from 
the  quarries  of  which  the  country  around  is  supplied  with  lime  and 
building  rock.  It  is  also  found  in  a  number  of  places  in  the  north- 
eastern township  of  the  county.  A  coal  mine  has  also  been  worked 
in  this  part  of  the  county,  the  bed  being  about  one  -  and  -  one  -  half 
feet  thick,  and  is  doubtless  the  same  one  which  is  found  near  Quincy 
in  Adams  county,  which  is  about  ten  miles  distant  from  that  point. 


64  REPORT  OF  STATE  GEOLOGIST. 

The  same  bed  may  probably  be  found  at  other  points  in  the  north- 
eastern part  of  Montgomery,  particularly  in  the  vicinity  of  the  mine 
which  has  been  worked.  In  an  easterly  and  westerly  direction  from 
that  point,  it  will  probably  be  found  not  to  vary  much  from  a  level 
with  it,  but  to  the  southward  the  dip  coincides  pretty  nearly  with  the 
fall  of  the  Nodaway.  Along  the  slopes  to  the  valley  of  the  Nishna- 
botany  a  heavy  bed  of  sandstone  appears  at  various  points,  which  is, 
however,  too  soft  to  be  used  as  stone,  except  in  some  instances  where 
iron  is  the  cementing  material.  In  such  cases,  irregular  layers  of 
very  hard,  dark  -  colored  stone  are  found  in  it,  which  will  serve  a 
very  good  purpose  for  walling  wells,  in  the  absence  of  better  mate- 
rial. 

Upon  the  first  examination  of  this  sandstone  it  was  found  to  rest 
unconformably  upon  the  upper  coal  -  measure  limestone,  and  was  sus- 
pected to  be  of  Cretaceous  age,  and  the  provisional  name  of  "Nish- 
nabotony  sandstone"  was  applied  to  it.  Subsequently  it  has  been 
proved  to  belong  to  that  age  by  the  discovery  of  characteristic  fossil 
leaves  in  the  exposure  within  the  village  of  Red  Oak. 

At  the  base  of  this  sandstone,  as  seen  on  land  of  Mr.  Johnson, 
section  2,  township  72,  range  38,  a  bed  of  clay  is  found  which  is  a 
mixture  of  a  dark  red  ochery  clay  with  that  of  nearly  a  white  color. 
The  latter  has  been  tested  for  the  manufacture  of  common  pottery 
and  pronounced  to  be  the  best  yet  found  in  the  southwestern  part  of 
the  State,  and  judging  from  its  appearance,  this  is  probably  correct. 
Clay  of  a  reddish  color,  and  doubtless  the  same  bed,  is  also  seen  in 
the  hillside  near  Stover's  Mill  on  the  Nishnabotany,  a  couple  of 
miles  below  Red  Oak.  This  clay,  with  the  exception  of  its  ochery 
ingredient,  is  similar  to  the  beds  of  fire-clay  which  underlie  the  beds 
of  coal  in  the  eastern  part  of  the  State,  and  it  is  not  improbable  that 
a  thin  bed  of  coal  may  yet  be  found  in  connection  with  this,  but 
there  is  little  hope  that  it  will  prove,  if  found,  of  sufficient  thickness 
to  be  profitably  worked.  Mr.  J.  B.  Packard,  of  Red  Oak,  exhibited 
some  material  which  he  had  used  for  paint,  having  the  appearance  of 
the  clay  above  mentioned,  but  containing  a  much  greater  proportion 
of  ochre  than  any  before  seen.  It  was  obtained  from  his  land  near 
Frankford,  in  this  county,  where  it  is  found  in  considerable  quantity. 
It  has  been  used  for  painting  barns  and  out  -  houses  for  a  number  of 


REPORT  OF  STATE  GEOLOGIST.  @5 

years,  and  seems  to  give  a  good  body  to  the  paint,  and  resembles, 
when  applied,  the  material  known  as  "Blake's  fire  -  proof  paint."  It 
is  of  a  dark  -  red  color,  suitable  for  bridges  and  barns,  but  is  too 
sombre  in  appearance  for  that  cheerfulness  which  should  characterize 
our  dwellings. 

The  soil  of  Montgomery  county  is  of  that  excellent  quality  which 
prevails  in  this  part  of  the  State,  and  it  needs  only  the  extensive 
planting  of  forest  trees,  and  railroad  -  communication,  to  make  it  as 
beautiful  and  prosperous  as  can  be  desired.  Even  now  many  neigh- 
borhoods give  evidence  of  wealth  and  prosperity  in  their  well  -  culti- 
vated farms,  large  herds  of  cattle  and  comfortable  homes. 

CASS  COUNTY. 

Cass,  although  only  the  second  county  from  the  Missouri,  is  yet 
the  most  easterly  one  of  the  third  tier  which  is  wholly  upon  the 
watershed  of  that  river. 

The  East  Nishnabotany  does  not  take  its  rise  in  this  county,  but 
it  nearly  loses  its  identity  here  by  its  subdivision  into  Indian,  Camp, 
Buck,  Turkey  and  Troublesome  creeks,  while  Seven  -  Mile  and  Six- 
teen -  Mile  creeks  form  the  head  waters  of  the  Nodaway,  and  com- 
plete the  drainage  of  the  county,  which  is  accomplished  in  the  same 
thorough  manner  as  that  of  those  which  adjoin  it. 

The  Nishnabotany  retains  its  broad,  beautiful  valley  as  far  up  as 
the  vicinity  of  Lewis,  the  county  -  seat,  where  it  passes  for  the  dis- 
tance of  a  few  miles  through  a  narrow  space  between  the  gently- 
sloping  hills,  without  the  broad  bottoms  which  characterize  it  below. 
Above  this,  the  valley  is  found  to  widen  again,  and  continues  thus 
as  far  up  as  the  sub  -  division  of  the  river  into  the  creeks  before 
mentioned. 

Interesting  as  the  characteristic  portion  of  the  valley  of  this  river 
is,  the  vicinity  of  Lewis  is  no  less  pleasant,  with  its  wooded  slopes 
and  gentle  declivities,  which,  together  with  the  valleys  of  the  creeks 
in  the  neighborhood,  give  a  pleasing  diversity  to  the  scenery  around. 

The  soil  of  Cass  county  is  of  that  abundant  and  uniform  fertility 
which  characterizes  this  portion  of  the  State,  and  some  of  it  has  the 
appearance  of  being  a  little  warmer,  from  a  slight  admixture  of  sand, 
doubtless  derived  from  the  cretaceous  sandstone  before  referred  to  as 


(JQ  REPORT  OF  STATE  GEOLOGIST. 

existing  in  Montgomery  county.  This  sandstone  is  found  at  a  num- 
ber of  places  along  the  Nishnabotany  and  its  tributaries,  in  this  coun- 
ty. Thus  far  it  has  been  also  seen  in  the  southeastern  part  of  Pot- 
tawattamie  and  the  northeastern  part  of  Mills  counties.  It  seems  to 
lie  in  detached  masses,  or  outliers,  rather  than  as  a  continuous  for- 
mation, and  the  greatest  thickness  yet  observed  is  thirty  feet.  Half 
a  mile  below  Lewis,  the  county  seat  of  Cass  county,  it  is  quarried  to 
a  considerable  extent.  The  stone  is  soft  when  first  taken  from  the 
quarry,  but  hardens  upon  exposure  to  the  atmosphere.  It  is  of  a 
brown  color,  and  in  ordinary  buildings  presents  a  sombre  appearance. 
There  are  certain  styles  of  architecture,  however,  in  which  this  color 
would  not  only  be  unobjectionable,  but  agreeable.  , 

The  upper  coal  -  measure  limestone  is  found  along  the  creeks  near 
the  border  of  Montgomery  county,  and  also  along  the  Nishnabotany 
and  its  branches.  The  supply  of  limestone  in  the  vicinity  of  Lewis 
is  abundant,  and  the  quality  good  both  for  building  and  the  manufac- 
ture of  lime.  The  western  part  of  the  county  is  quite  well  supplied 
with  timber,  but  there  is  a  deficiency  of  fuel  in  the  eastern  part. 

No  coal  has  yet  been  found  in  this  county,  but  it  is  not  improbable 
that  the  bed  now  worked  near  Quincy  in  Adams  county,  and  also  in 
the  northeastern  corner  of  Montgomery  county,  may  be  found  to 
exist  in  this  also.  Should  this  be  the  case  it  will  probably  be  found 
no  thicker,  if  so  thick  as  it  is  there. 

ADAMS  COUJNTY. 

Adams,  like  all  other  counties  of  the  "Missouri  slope,"  is  a  well- 
drained,  yet  a  well  -watered  county  ;  the  drainage  being  effected  prin- 
cipally by  the  West  and  Middle  Nodaways  and  their  tributaries, 
which  also  furnish  excellent  water  for  stock;  and  in  addition  to  this 
the  two  rivers  furnish  a  number  of  good  mill  privileges.  Good  wells 
are  obtained  at  a  moderate  depth  in  all  parts  of  the  county ;  it  has 
fully  an  average  supply  of  timber,  a  considerable  supply  of  stone, 
and  more  coal  which  is  now  accessible  than  any  other  county  to  the 
westward  of  or  adjoining  it.  Its  soil  is  also  of  the  same  excellent 
quality  which  prevails  in  this  part  of  the  State. 

If  the  county  be  divided  through  its  center  from  north  to  south  the 
advantages  of  its  resources  are  found  to  be  singularly  in  favor  of  the 


REPORT  OF  STATE  GEOLOGIST.  gf 

western  half,  for  although  the  eastern  half  possesses  an  excellent  soil, 
a  little  timber — which  is  principally  along  the  Nodaway — and  good 
water,  yet  the  western  half  has,  in  addition  to  these,  a  very  good 
supply  of  timber,  and  all  the  coal  and  stone  yet  found  in  the  county, 
as  well  as  all  the  valuable  water  power.  The  valleys  of  the  Noda- 
ways  are  narrower  in  this,  than  in  the  counties  of  Page,  Taylor,  and 
Montgomery,  but  they  are  yet  beautiful  and  fertile.  The  timber  is 
rapidly  encroaching  upon  the  prairies  from  the  borders  of  the  streams, 
because  the  inhabitants  keep  the  fires  out  in  protection  of  their  farms. 
Stone,  good  enough  for  ordinary  purposes,  is  found  in  every  town- 
ship of  the  western  half,  and  coal  is  mined  at  intervals  along  the  West 
Nodaway  from  Harader's  Mill,  three  miles  north  of  Quincy,  to  about 
the  same  distance  below  the  town,  on  land  owned  by  the  Drs.  Raw- 
son  of  that  place. 

Near  the  middle  at  the  crossing  of  the  river,  two  miles  westward 
from  Quincy,  several  openings  have  been  made  and  considerable  coal 
taken  out.  Near  this  place  Messrs.  Barnett  and  Smith  have  sunk  a 
shaft  to  a  depth  of  about  forty  -  five  feet  below  the  bed  of  coal  they 
are  now  working  with  the  hope  of  finding  a  still  lower  bed.  They 
have  for  the  present  discontinued  their  work  upon  it  with  the  inten- 
tion of  resuming  it.  Such  an  enterprise  is  not  unreasonable, 
although  undertaken  without  any  previous  experience  in  that  direc- 
tion in  this  part  of  the  State,  for  the  bed  they  are  now  working  is  the 
same  one  which  is  worked  in  Taylor,  Page  and  Montgomery  coun- 
ties, and  the  only  bed  yet  discovered  upon  the  "Missouri  slope," 
south  of  the  north  line  of  the  third  tier  of  counties.  This  bed  of  coal 
also,  as  well  as  all  the  other  strata  which  appear  in  Adams  county, 
belong  higher  in  the  series  than  the  productive  coal  -  beds  along  the 
Des  Moines  river.  As  yet,  however,  we  have  had  too  little  experi- 
ence in  our  own  coal  -  field  to  give  positive  encouragement  to  these 
gentlemen  to  continue  their  work,  although  it  would  be  perfectly  in 
accordance  \vith  the  principles  of  geology  to  do  so,  taking  the  hazard 
of  those  beds  having  thinned  out  before  reaching  so  far  westward. 
Should  these  lower  beds  exist  there,  it  is  not  believed  that  they  lie 
at  an  impracticable  depth,  but  this  is  a  question  which  must  be  deci- 
ded alter  further  investigation. 

The  people  of  this  county  give  evidence  of  much  thrift  and  public 


gg  REPORT  OF  STATE  GEOLOGIST.. 

spirit,  and  even  the  eastern  half  possesses  many  bright  spots,  made 
so  by  the  strong  hand  of  honest  toil,  the  society  of  which  would  shed 
lustre  and  benefit  on  any  part  of  the  older  States. 

ADAIR  COUNTY. 

Adair  County  lies  directly  upon  the  dividing  ridge  between  the 
watersheds  of  the  Mississippi,  and  Missouri  rivers.  It  is  in  this 
county  that  Grand,  and  the  East,  and  Middle  Nodaway  rivers  have 
their  rise  ;  and  North  and  Middle  rivers  are  small  prairie  streams 
where  they  enter  its  borders.  The  surface  of  the  county  is  almost 
entirely  prairie,  for  its  streams  are  all  small,  although  called  "  rivers," 
and  as  is  usually  the  case  with  small  streams  in  this  part  of  the 
State,  very  little  timber  is  found  along  their  borders.  There  is, 
however,  a  sufficient  supply  of  fuel  of  this  kind  for  the  present 
inhabitants. 

The  drainage  of  the  county  is  perfect,  and  yet  there  is  no  diffi- 
culty in  getting  water  for  stock  from  the  numerous  streams,  and  for 
domestic  use,  from  wells  and  springs.  The  surface  is  more  deeply 
cut  by  the  streams  and  their  tributary  branches  and  ravines  than 
one  would  expect  to  see  in  a  regions  lying  upon  a  "  divide/'  which 
gives  an  unevenness  of  surface,  which  near  the  streams  is  too  great 
for  convenient  farming. 

The  soil  however,  is  everywhere  good,  as  in  the  neighboring 
counties,  and  this  broken  region  will  afford  excellent  pasturage  for 
sheep,  either  with  the  wild,  or  cultivated  grasses. 

The  only  stone  found  in  the  country  —  except  the  drift  boulders 
—  appear  along  Middle  River,  at  frequent  intervals  from  about  three 
miles  south  of  the  northern  boundary,  to  where  the  river  enters 
Madison  county,  about  the  middle  of  the  east  line  of  Adair.  At 
various  points  near  the  river  in  township  76,  range  30,  almost  any 
desired  quantity  of  limestone  can  be  obtained,  which  for  making 
lime,  and  for  the  purposes  of  ordinary  masonry,  is  very  good.  Near 
the  heads  of  Grand  River  a  number  of  large  boulders,  quite  large 
for  this  latitude,  are  to  be  seen,  the  home  of  which,  as  almost  every 
one  knows,  is  far  to  the  northward. 

On  section  22,  township  25,  range  32,  a  dark  carbonaceous  matter 
was  found  by  the  citizens  exposed  in  a  small  branch  of  the  Middle 


REPORT  OF  STATE  GEOLOGIST.  59 

Nodaway,  and  a  shaft  of  a  few  feet  in  depth  was  sunk  down  to  it 
from  the  bank. 

This,  at  the  time  of  my  visit,  was  partly  filled  with  water,  the 
work  having  been  discontinued.  By  bailing  it  out  with  a  bucket,  a 
view  of  the  bed  was  obtained  and  some  specimens  secured  for  further 
examination.  It  has  the  appearance  of  impure  coal,  but  lacks  the 
characteristic  angular  fracture  of  bituminous  coal.  No  specimens 
have  yet  been  obtained  beyond  the  action  of  the  atmosphere  and 
frost,  and  when  worked  farther  beneath  the  hill  it  may  prove  to  be  a 
valuable  article  of  fuel,  particularly  in  a  region  where  timber  is  so 
scarce. 

It  is  possible  that  this  is  the  northern  extension  of  the  bed  now 
worked  at  Quincy  and  elsewhere.  It  so,  it  may  prove  more  valuable 
than  present  appearances  would  indicate,  beside  which,  it  is  thicker 
here  than  the  Quincy  bed  has  yet  been  found. 

UNION  COUNTY. 

With  the  exception  of  half-  a  -  dozen  square  miles  of  the  extreme 
northeast  corner  of  Union,  which  are  drained  into  Clanton's  fork  of 
Middle  river,  the  whole  of  Union  county  lies  upon  the  Missouri 
watershed,  and  is  drained  principally  by  Thompson's  fork  of  Grand 
river.  Highland,  near  the  center  of  the  county,  is  the  highest  land 
between  the  Mississippi  and  Missouri  rivers  on  the  line  of  the  Bur- 
lington and  Missouri  River  Railroad,  being  twelve  hundred  and 
eighty  -  seven  feet  above  the  level  of  the  Gulf  of  Mexico,  and  eight 
hundred  and  one  feet  above  low  water  in  the  Mississippi  river  at 
Burlington.  The  county  is  of  th<}  same  size  and  shape  as  Adams, 
which  borders  it  on  the  west,  and  if  divided  through  the  center  from 
north  to  south  the  west  half  would  be  found  in  all  respects  similar 
to  the  eastern  half  of  that  county  in  its  prairie  surface,  being 
sparsely  supplied  with  timber,  and  also  in  containing  no  quarry  rock. 
The  eastern  half  contains  a  considerable  amount  of  timber  along 
Grand  river  and  its  tributaries,  and  from  the  vicinity  of  Afton  to  the 
southeast  cornsr  of  the  county,  good  quarry  rock  may  be  readily 
obtained  at  frequent  intervals.  This  rock  is  of  good  quality  for 
building  purposes,  and  the  greater  part  of  it  will  make  excellent 
lime,  of  which  necessary  material  the  inhabitants  of  some  portions 


70  REPORT  OF  STATE  GEOLOGIST. 

of  the  neighboring  counties  obtain  their  supplies  from  this.  The 
soil  of  Union  is  excellent,  and  practically  identical  with  that  of  all 
those  which  adjoin  it  upon  the  southward  and  westward,  being  cov- 
ered like  those  counties  with  a  heavy  deposit  of  drift  material. 

XA11  the  stratified  rocks  found  in  this  county  belong  to  the  upper 
series  of  coal  -  measure  strata,  so  that  there  is  little  hope  of  finding 
a  workable  bed  of  coal  above  the  level  of  its  deepest  valleys,  unless 
the  bed  now  being  worked  in  Adams  county  shall  be  found  to  extend 
into  this.  Even  then  it  would  probably  be  found  to  be  very  thin. 
There  is  hope,  however,  that  coal  may  yet  be  found  at  an  available 
depth  beneath  the  surface. 

It  was  observed  that  fruit  -  trees  grow  thriftily  in  this  county, 
wherever  they  have  been  planted,  and  Mr.  John  C.  Wicks,  who  lives 
a  few  miles  south  -  east  from  Afton,  has  succeeded  admirably  in  cul- 
tivating the  principal  fine  varieties  of  grapes,  of  which  he  has  a 
flourishing  little  vineyard. 

This,  like  the  neighboring  counties,  beside  being  well  watered  by 
its  streams  furnishes  wells  of  pure,  cold  water,  wherever  the  neces- 
sities of  the  inhabitants  require  them  to  dig  one. 

The  number  of  inhabitants  is  rapidly  increasing  by  settlement, 
attracted  hither  by  the  natural  advantages  which  the  county  affords, 
and  also  those  in  the  immediate  future  to  be  derived  from  the  early 
completion  of  the  Burlington  and  Missouri  River  Railroad,  which  is 
to  pass  westward  nearly  through  its  centre,  and  will  soon  place  its 
inhabitants  in  direct  communication  with  both  the  Atlantic  and 
Pacific  sea  -  boards. 

MADISOST  COUNTY. 

The  upper  coal  -  measure  series  of  strata  are  more  fully  developed 
in  this,  than  in  any  other  county  yet  examined,  and  in  the  deep- 
er valleys.  The  general  dip  of  all  the  strata  is  found  in  the  southern 
part  of  the  State,  to  be  nearly  or  quite  coincident  with  the  fall  of  the 
streams.  But  in  the  "Three  -  river  country,"  as  that  region  has  been 
called,  which  is  drained  by  South,  Middle  and  North  rivers,  the 
drainage  is  to  the  eastward.  Consequently  in  that  portion  of  the 
region  toward  the  drainage  of  the  Racoon  fork  of  the  Des  Moines, 
one  would  expect  to  find  the  lower  series  of  coal  -  measure  strata 


REPORT  OF  STATE  GEOLOGIST.  71 

nearer  the  surface  than  they  are  farther  to  the  southward.  This  is 
actually  the  case,  and  although  along  Middle  river  from  the  middle 
to  the  western  part  of  the  county,  the  upper  series  is  in  full  force, 
before  reaching  the  north-eastern  part  of  it,  they  have  nearly  or 
quite  disappeared,  and  the  strata  of  the  middle  series  only  are  seen. 
These  well  -  developed  features  of  the  geology  of  Madison  county  are 
not  only  of  great  interest  within  its  own  borders,  but  the  facility 
afforded  here  for  observing  so  complete  a  series,  necessarily  makes 
the  results  of  such  observations  the  standard  of  comparison  for  sim- 
ilar investigations  over  the  whole  region  occupied  by  corresponding 
strata 

The  subject  of  coal  in  this  county  has  received  as  much  attention 
as  it  was  possible  to  bestow  upon  it,  the  results  of  which  have  thus 
far,  been  only  partially  satisfactory.  From  the  mud  -sill  of  Comp- 
ton's  mill  on  Middle  river,  one  and  a  half  miles  southward  from  Win- 
terset,  to  the  level  of  the  town  plat,  is  about  two  hundred  and  thirty 
feet  in  perpendicular  height.  The  upper  fifty  feet  of  this  is  com- 
posed of  soil,  sub  -  soil  and  drift  material.  The  remainder,  except 
the  stratum  upon  which  the  mud  -  sill  of  the  mill  rests  is  at  present 
all  referred  to  the  upper  coal  -  measures,  the  lowest  stratum  probably 
belongs  to  the  middle  coal  -  measures,  although  at  first  supposed  to 
belong  to  the  lower. 

The  following  is  a  section  of  the  rocks  exposed  in  the  valley  of  a 
small  creek  a  little  southward  from  Winterset,  numbered  from  the 
top  downward,  omitting  the  fifty  feet  of  drift  which  covers  the  whole 
and  which  forms  the  surface  deposit  of  the  region  around. 

SECTION   OF   THE   ROCKS   NEAR   WINTERSET. 

No.  1.  Thin  bedded  yellowish  limestone 1  foot. 

No.  2.  Light-bluish  marlite 4  " 

No.  3.  Gray,  massive  limestone  with  dull  fracture 6  " 

No.  4.  Gray,  regularly  bedded  limestone  with  conchoidal  fracture 12  " 

No.  5.  Black,  laminated,  carbonaceous  shale 2  " 

No.  6.  Gray  limestone  with  marly  partings  like  No.  4 34  " 

No.  7.  Black  shale  like  No.  5  .. 2i  " 

No.  8.  Regularly  bedded  gray  limestone  with  many  cherty  layers 15  " 

No.  9.  Compact  limestone  with  concretionary  structure 2  " 


72  REPORT  OF  STATE  GEOLOGIST. 

No.  10.  Limestone  of  varying  quality  —  in  some  parts  siliceous  and 
same   of  the   interestitial    material    micaceous    and  finely 

arenaceous 16|    foot 

No.  11.  Impure  coal i    " 

No.  12.  Light  blue  marlite 2      " 

No.  13.  Bluish,  concretionary  limestone,  breaking  readily  into  small 

fragments 5      " 

No.  14.  Bluish  and  reddish  clays .' .       6      " 

No.  15.  Sandy,  micaceous  shale,  with  fine  grained  micaceous  sand- 
stone in  thin  layers  of  bluish  and  greenish  colors 71      " 

No.  16.  Bluish,  shaly,  impure  limestone  seen  in  the  bed  of  the  river  at 

Compton's  mill , 2      " 

1811  feet. 

As  one  goes  from  the  town  to  Compton's  mill,  on  Middle  river, 
two  miles  southward  from  Winterset,  he  passes  down  through  each 
successive  stratum,  as  it  were,  the  small  stream  along  which  the  road 
runs  having,  in  former  ages,  worn  its  valley  through  them,  leaving 
the  edges  of  the  firmer  ones  appearing  at  intervals  in  the  sides  of 
the  hills,  while  those  of  softer  material  are  obscured  by  disinte- 
gration. 

By  digging  down  beneath  the  stratum  No.  16  at  several  places  in 
the  vicinity,  a  very  thin  seam  of  coal  was  found.  Thus  it  will  be 
seen  that  although  two  coal  horizons  exists  in  the  series  of  rocks 
exposed  here,  besides  the  two  beds  of  carbonaceous  shale,  there  is 
little  hope  of  finding  a  workable  bed  of  coal  near  Winterset,  above 
the  level  of  Middle  river. 

Going  twelve  miles  northward  from  Winterset,  in  which  direction 
as  before  said  the  upper  strata  disappear,  the  bed  numbered  16  is 
found  exposed  in  the  right  bank  of  the  north  fork  gf  North  river, 
and  thirteen  feet  of  bluish  shale  underlaid  by  a  bed  of  coal,  all 
appearing  beneath  it. 

Working  of  the  coal  was  suspended  at  the  time  the  locality  was 
visited  so  that  only  one  and  a  half  feet  of  its  thickness  was  seen. 
Mr.  George  Clarke,  the  owner  of  the  property,  reports  the  coal  to 
be  two  and  a  half  feet  thick,  which  no  reason  was  seen  to  doubt. 
Some  twelve  miles  southward  from  Winterset,  at  and  near  Ander- 
son's mill,  on  Clanton's  fork  of  Middle  river,  the  same  bed  is 
recognized,  but  it  is  there  only  eight  or  nine  inches  thick. 


REPORT  OF  STATE  GEOLOGIST.  73 

These,  so  far  as  known,  are  the  only  exposures  of  coal  yet  found 
in  Madison  county,  but  since  the  productive  coal-measures  lie  beneath 
all  the  strata  found  in  this  county,  there  is  a  reasonable  hope  that 
an  abundant  supply  may  be  obtained  by  sinking  shafts.  These 
should  of  course  be  commenced  in  the  valleys  because  they  are 
already  cut  out  of  the  strata  which  must  be  bored  through  before 
reaching  the  level  of  the  streams  if  commenced  on  the  high  lands. 
It  is  believed  that  coal  would  be  reached  within  one  or  two  hundred 
feet  from  the  valley  bottoms,  but  no  exact  estimates  can  yet  be  given. 

The  beds  No.  5  and  No.  7  being  a  black  carbonaceous  shale  are 
often  regarded  by  the  people  as  an  indication  of  coal,  but  although 
they  are  often  found  associated  with  coal  -  beds,  yet  their  presence  is 
of  no  value  for  such  purposes. 

At  a  number  of  places  in  the  vicinity  of  Winterset,  bed  No.  3  of 
the  preceding  section  furnishes  unusually  fine,  massive  blocks  of  grey 
limestone  which  are  largely  used  in  that  region  for  building  purposes, 
and  dressed  blocks  of  it  have  also  been  carried  as  far  as  the  capital 
on  common  wagons. 

The  time  will  soon  come  when  the  counties  which  adjoin  this  upon 
the  south  and  west  at  least,  will  require  facilities  for  obtaining  the 
stone  which  is  so  abundant  along  all  the  rivers  of  this  county.  The 
other  beds  of  limestone  beneath  the  massive  one  just  mentioned  also 
furnish  immense  quantities  of  stone  for  lirne,  and  for  ordinary  mason- 
ry, while  there  is  enough  broken  stone  in  the  beds  of  its  streams 
alone  to  McAdamize  all  its  roads. 

Timber  of  excellent  growth  and  quality  is  also  so  abundant  along 
the  streams  as  to  make  it  desirable  to  check  rather  than  encourage 
its  encroachment  upon  the  prairies.  These  streams  afford  good 
water,  and  upon  the  larger  ones  are  numerous  valuable  water  privi- 
leges, many  of  which  are  improved  by  the  erection  of  substantial 
woolen,  flouring  and  saw  mills. 

The  quality  of  the  soil  is  not  surpassed  anywhere,  and  the  general 
aspect  of  the  county  is  one  of  unusual  beauty.     The  monotony  which 
often  accompanies  prairie  views  is  here  completely  relieved  by  gentle 
undulations,  and  the  wooded  hillsides  and  valleys. 
10 


74  REPORT  OF  STATE  GEOLOGIST. 

SALT. 

The  following  article  was  written  and  published  in  the  newspapers 
as  a  reply  to  numerous  enquiries  by  letter  from  different  parts  of  the 
State  as  to  the  prospect  of  finding  salt  in  Iowa  in  paying  quantities, 
particularly  in  Davis  county,  where  u  saline  lands  "  have  long  been 
understood  to  exist : 

By  the  word  salt,  we  invariably  mean  in  common  language,  what 
the  chemist  invariably  means  by  "  chloride  of  sodium,"  and  no  one 
misunderstands  us.  But  he  uses  the  same  word  in  a  far  more  exten- 
ded sense  than  we,  and  makes  it  signify  any  substance  which  results 
from  the  chemical  union  of  any  acid  with  any  base.  Consequently 
he  has  almost  an  infinite  number  of  different  salts,  some  of  which 
readily  dissolve  in  water,  but  many  others  are  as  insoluble  as  the 
rocks  themselves ;  and  a  part  of  these  are  indeed  nothing  more  or 
less  than  chemical  salts.  Thus  nature  also  produces,  in  her  chemicak 
laboratory,  both  soluble  and  insoluble  salts  ;  that  is,  soluble  or  insol- 
uble in  water.  The  most  abundant  of  the  latter  is  limestone  ;  of  the 
former,  salt.  Further  on,  water  saturating  the  earth  under  certain 
circumstances  will  be  mentioned.  This,  all  will  understand.  We 
shall  also  speak  of  water  being  saturated  with  salt.  This  is  the 
chemists'  use  of  the  word,  and  signifies  in  this  instance,  water  having 
dissolved  all  the  salt  of  which  it  is  capable,  when  any  more  being 
added  would  fall  to  the  bottom  and  remain  there  undissolved.  When 
water  is  fully  saturated,  it  contains  about  36  per  cent,  of  salt, 
whether  hot  or  cold. 

In  writing  upon  subjects  related  to  chemistry,  one  is  often  obliged 
to  make  use  of  some  of  its  technicalities ;  hence  these  few  words  ot 
explanation.  The  sea,  as  every  one  knows,  is  the  great  repository 
of  common  salt,  but  perhaps  every  one  does  not  know,  which  is 
really  the  case,  that  sea  water  also  holds  in  solution  many  other 
salts  besides  this,  but  in  very  much  smaller  proportion.  These  are 
almost  the  sole  cause  of  the  impurity  of  all  salt  artificially  manu- 
factured from  sea  water.  When  good  salt  is  produced  from  sea 
water,  as  is  now  the  case  on  Turk's  Island  and  many  other  parts  of 
the  world,  it  is  by  a  natural  purifying  process  of  crystalization, 
resulting  from  the  slow  evaporation  of  the  water  by  the  heat  of 


REPORT  OF  STATE  GEOLOGIST.  75 

the  sun,  which  affords  time  for  the  chemical  separation  of  the 
other  salts,  which  is  only  partially  accomplished  by  the  artificial 
process.  All  the  salt  obtained  as  such,  from  the  mines  of  different 
parts  of  the  world,  are  believed  to  have  been  originally  produced 
from  sea  water  by  a  natural  process,  similar  to  the  one  referred*,  to, 
at  a  time  when  tho  place  which  the  deposit  now  occupies,  formed 
a  broad  shallow  lagoon  near  the  shore  of  a  then  existing  sea,  and 
with  which  it  communicated  at  full  tide.  As  the  sea  receded,  by 
the  ebb  of  the  tide,  evaporation  of  the  shallow  water  of  the 
lagoon  continued  without  interruption,  leaving  behind  a  greater 
amount  of  salt  than  served  to  saturate  it.  This  excess  of  salt 
constantly  increased,  because  nothing  but  pure  water  passed  off 
as  a  vapor,  and  because  every  returning  flood  of  the  tide  brought 
more  salt  as  well  as  more  water,  until  the  lagoon  was  filled  with  salt, 
and  would  receive  no  more  water  from  the  sea.  This  process  may 
now  be  observed  in  several  parts  of  the  world,  and  should  some 
geological  change  of  the  earth's  surface  take  place,  as  they  have 
taken  place  in  past  ages,  to  bury  these  salt  deposits  beneath  the 
earth,  the  salt  there  would  be  in  the  same  condition  as  that  of  the 
mines  of  England,  Poland,  and  other  parts  of  the  world.  Thus  we 
see  that  the  salt  of  mines,  although  deep  within  the  bowels  of  the 
earth,  has  doubtless  been  derived  from  the  sea,  or  from  an  inland 
salt  lake  where  it  has  accumulated  by  a  process  presently  to  be 
described.  But  notwithstanding  this  fact,  the  original  home  of  the 
salt  is  in  the  earth,  and  not  in  the  sea,  for  it  is  believed  that  all 
the  water  upon  the  earth  once  existed  in  the  form  of  vapor  diffused 
in  the  atmosphere  surrounding  a  red-hot  world,  and  vapor  can 
contain  no  common  salt. 

After  the  surface  had  cooled  sufficiently  'to  form  a  crust,  the  vapor 
began  to  condense ;  and  these  first  rains  were  as  fresh,  so  far  as 
containing  common  salt  is  concerned,  as  those  which  fall  upon  our 
heads  to  -  day.  The  first  seas  were  formed  by  the  rains,  in  the 
depressions  which  they  found  upon  the  surface,  and  their  waters 
were  comparatively  fresh,  for  nearly  all  the  soluble  salts,  (of  which 
salt  is  the  chief,)  or  their  chemical  constituents,  were  yet  dissem- 
inated in  the  substance  of  the  earth.  A  still  further  cooling  of  the 
earth's  crust,  and  disintegration  of  its  substance,  admitted  free 


76  REPORT  OF  STATE  GEOLOGIST. 

percolation  of  the  water  which  fell  upon  its  surface  and  which  in 
its  passage  again  to  the  sea,  took  up  the  soluble  salts  with  which  it 
came  in  contact  in  its  terrestrial  passage,  in  addition  to  those  which 
may  have  existed  in  the  bed  upon  which  the  sea  was  formed.  Thus 
the  sea  has  derived  all  its  salt  from  the  earth  by  a  process  of  leach- 
ing similar  to  that  by  which  the  frugal  housewife  obtains  potash -lye 
in  the  domestic  manufacture  of  soap.  Thus  its  waters  have  constantly 
increased  in  saltness  from  the  earliest  to  the  present  time ;  for  the 
rivers  of  the  world  are  even  now  carrying  down  salt  to  the  sea, 
although  the  amount  of  their  water  is  proportionally  so  great  that 
it  is  perceptible  only  by  the  most  careful  analysis.  The  immense 
amount  of  fresh  water  constantly  poured  into  the  sea  does  not 
diminish  its  saltness  by  dilution,  but  on  the  contrary,  constantly 
increases  it  by  addition  of  salt,  while  the  same  amount  of  water 
which  the  rivers  bring,  is  returned  to  the  earth  again  by  evaporation. 
Whenever  the  relative  positions  of  sea  and  land  have  been 
changed,  and  such  changes  have  been  many  in  past  geological  ages, 
every  lake  which  may  have  resulted  from  the  elevation  of  land  from 
the  bottom  of  the  sea,  was  as  salt  when  it  was  first  formed,  as  the 
sea  from  which  it  derived  its  waters ;  but  when  such  a  lake  had  an 
outlet,  the  accumulation  of  waters  beyond  and  around  its  surface  by 
drainage,  soon  rendered  it  as  fresh  as  the  streams  which  emptied 
into  it.  But  where  such  a  lake  or  inland  sea  has  no  outlet,  the  sur- 
face would  rise  or  fall  to  a  level  at  which  the  evaporation  just 
equalled  the  supply  of  water,  which  level  would  have  no  necesary 
relation  to  that  of  the  great  sea,  which  is  also  determined  by  the 
same  law.  Such  a  lake  would  increase  in  saltness  from  the  same 
cause  that  the  sea  has  done,  but  more  rapidly  if  the  area  drained 
into  it  contained  more  than  the  average  amount  of  soluble  salts. 
When  the  salt  in  the  water  of  such  a  lake  had  increased  to  the 
degree  of  saturation,  it  would  commence  to  be  precipitated,  and  form 
upon  the  bottom,  a  bed  of  crystalline  salt.  This  is  actually  the  case 
in  Great  Salt  Lake,  as  well  as  in  others.  But  still  other  salt  lakes  and 
inland  seas  have  not  yet  reached  this  point  of  saturation,  and  they 
consequently  precipitate  no  more  salt  than  the  great  sea  does. 
Should  Great  Salt  Lake  is  future  geological  times  become  buried 
under  other  strata  of  the  earth,  its  bed  would  be  a  subterranean 


REPORT  OF  STATE  GEOLOGIST.  77 

deposit  of  salt,  similar  to  some  that  are  now  known,  which,  doubtless', 
had  a  similar  origin,  if  they  did  not  originate  in  lagoons  as  before 
described.  The  salt  of  such  a  deposit  might  never  have  had,  either 
directly  or  indirectly,  any  connection  with  the  sea,  any  more  than 
the  salt  of  Great  Salt  Lake  has  had. 

Although  the  earth,  and  not  the  sea  is  the  original  home  of  the 
salt,  yet  in  the  various  elevations  of  the  land  above  the  sea,  composed 
of  strata  which  were  formed  there,  or  of  the  muddy  sediment  of 
marshes  which  existed  upon  its  borders,  it  was  impossible  that  they 
should  not  have  retained  within  their  substance  some  of  the  salt  of 
the  water  with  which  they  have  been  constantly  saturated,  and  in 
this  sense  some  of  the  salt  disseminated  throughout  the  substance  of 
the  earth,  may  be  said  to  have  been  derived  from  the  sea.  Now 
when  these  strata,  which  are  always  more  impervious  to  water  ver- 
tically, than  horizontally,  were  elevated,  they  were  almost  never  left 
in  the  horizontal  position  in  which  they  were  deposited,  but  in  the 
movement  of  elevation  were  more  or  less  tilted,  so  that  drainage  by 
percolation  could  take  place  throughout  the  mass  in  the  direction  of 
the  interstices  between  the  layers,  and  the  greater  part  of  the  salt 
they  may  have  contained  was  thus  really  carried  back  to  the  sea 
again.  But  suppose  a  series  of  such  strata,  composed,  as  is  usually 
the  case,  of  material,  alternating,  more  and  less  impervious  to  water, 
to  have  been  elevated  in  such  a  manner  that  their  dip  around  the 
whole  area  which  they  occupied  should  be  toward  the  center,  and 
they  resting  upon  each  other  like  a  pile  of  saucers  in  the  dish  -  pan 
of  the  housewife  with  the  water  between  them.  In  such  a  case  all 
the  saline  substances  they  may  have  contained  at  the  time  of  their 
elevation  would  remain  there  just  as  the  water  would  remain  in  the 
saucers  if  carefully  lifted  from  the  pan.  Water  would  indeed  pen- 
etrate the  mass  by  percolation  from  the  surface  but  find  no  channel 
out,  would  escape  only  by  the  ordinary  process  of  evaporation  from 
the  same  surface,  leaving  all  the  saline  matter  behind.  Consequently 
upon  boring  down  through  the  mass,  water  would  be  obtained  in 
those  strata  which  are  most  permeable  by  it,  and  this  would  be  found 
to  be  salt  water.  Such  a  condition  of  strata  actually  exists,  occu- 
pying nearly  the  whole  southern  peninsula  of  Michigan,  as  was  first 
pointed  out  by  Prof.  Alexander  Winchell,  the  State  Geologist,  to  the 


fg  REPORT  OF  STATE  GEOLOGIST. 

correctness  of  whose  predictions  in  relation  to  the  abundance  of  salt 
his  State  would  soon  produce,  every  market  in  the  country  now  gives 
ample  testimony. 

The  salt  of  the  Michigan  brine  may  never  have  existed  in  the 
crystalline  form  since  it  was  first  leached  into  the  sea  from  the  place 
of  its  original  distribution,  but  brine  is  sometimes  obtained  from  the 
earth  which  hay  probably  derived  its  salt  from  such  deposits  as  have 
just  been  referred  to,  in  its  passage  through  them  beneath  the  earth. 
Such  deposits  are  sometimes  found  containing  so  much  earthy 
admixture  that  to  obtain  the  s  <lt  in  an  available  form,  fresh  water  is 
artificially  added  to  produce  a  brine,  from  which  it  is  then  manufact- 
ured in  the  usual  manner.  Thus  we  see  that  the  present  distribu- 
tion of  salt  in  the  earth  has  originated  from  a  variety  of  causes.  It, 
or  its  component  elements  were  originally  disseminated  throughout 
the  substance  of  the  earth,  the  greater  part  of  which  has  been 
carried  to  the  sea  by  a  leaching  process  of  nature ;  that  the  stratified 
rocks  have  salt  also  disseminated  through  them  as  a  result  of  satura- 
tion by  the  sea  water  in  which  they  were  deposited ;  that  it  exists 
also  in  the  earth  as  an  accumulation  of  brine ;  as  subterranean 
deposits  of  crystalline  salt  derived  from  ancient  lakes,  lagoons  and 
marshes,  and  finally  as  brine  formed  from  such  deposits  by  the 
percolation  of  fresh  water  through  them.  It  is  only  by  the  three 
latter  methods  that  a  sufficient  accumulation  has  taken  place  in  the 
earth  to  render  its  production  possible  in  such  quantities  as  our 
necessities  require. 

The  question  then  very  naturally  arises  :  have  we  in  Iowa  any 
evidence  of  the  existence  of  deposits  of  salt,  or  of  a  condition  of 
the  strata  which  would  retain  the  brine  of  the  sea  in  which  they 
were  deposited?  As  regards  deposits  of  salt  beneath  the  surface  of 
our  State,  while  we  have  yet  no  evidence  that  any  such  exist  in  the 
crystalline  form,  we  certainly  have  none  that  they  may  not  yet  be 
discovered.  There  are  springs  in  different  parts  of  the  State,  the 
waters  of  which  contain  small  quantities  of  salt,  but  so  far  as  I  am 
yet  aware,  these  are  all  confined  to  those  regions  underlaid  by  coal- 
measure  strata.  It  is  possible  that  this  salt  is  derived  from 
crystalline  deposits  of  that  material,  but  we  have  yet  no  evidence  of 
the  existence  of  them.  If  the  coal  with  some  of  its  associated  strata 


REPORT  OF  STATE  GEOLOGIST.  .  79 

were  formed  in  broad  marshes  in  close  connection  with  the  sea  level, 
as  is  generally  believed,  then  we  may  infer  that  the  salt  of  the  coal- 
measure  strata  of  Davis  county  was  derived  from  that  which  was 
then  freely  distributed  throughout  those  marshes.  Whatever  may 
have  been  its  origin,  the  reason  that  it  remains  in  those  strata  may 
be  due  to  the  fact  that  while  the  general  dip  of  all  the  strata  of  the 
State  is  to  the  southward ;  there  is  also  a  slight  counter  dip  to  the 
westward  in  the  southeastern  part,  forming  at  least  two  sides  of  a 
very  shallow  depression  in  the  strata  (not  in  the  surface),  which  may 
have  served  to  collect  the  saline  matters  of  the  strata  there  into  that 
region,  of  which  the  northeastern  part  of  Davis  county  may  proba- 
bly be  a  centre.  »  Some  of  these  waters  have  been  analyzed,  and 
proving  to  contain  less  than  one  per  cent  of  salt  the  prospect  of 
obtaining  it  in  paying  quantities  is  not  now  encouraging.  Yet,  as 
before  intimated,  there  are  no  positive  reasons  why  it  may  not  exist 
in  such  quantities  in  our  State. 


SECOND  ANNUAL  REPORT 

OP 

CHARLES  A.  WHITE,  M.  D.,  STATE  GEOLOGIST. 


To  His  Excellency,  William  M.  Stone,  Governor  of  Iowa  : 

SIR  :  I  herewith  transmit  to  you  my  second  annual  report  of  progress  of  the 
State  Geological  Survey,  together  with  copies  of  reports  of  Mr.  O.  H.  St.  John, 
Assistant,  and  Prof.  Gustavus  Hinrich,  Chemist. 

I  also  herewith  transmit,  as  a  part  of  my  report,  copies  of  fourteen  letters  in 
relation  to  the  geological  work,  which  I  have  prepared  and  published  from  time 
to  time  in  the  newspapers  of  the  State,  in  accordance  with  the  provisions  of  law. 
Accompanying  these  are  also  copies  of  a  number  of  letters  prepared  and  similarly 
published  by  Professor  Hinrichs  and  Mr.  St.  John. 

Immediately  after  my  first  annual  report  of  progress  to  you,  I  commenced  the 
arrangement  and  study  of  the  collections  made  during  the  previous  season,  and 
also  the  preparation  of  papers  upon  subjects  connected  with  the  State  Geologica 
Survey,  for  publication  in  the  scientific  journals.  These  were  duly  credited  to  the 
survey  in  the  imprint  of  their  titles,  so  that  the  State  should  receive  credit  for 
the  priority  of  investigation  and  discovery,  which  would  otherwise  be  in  danger 
of  loss  by  delay  of  their  publication  in  our  final  report. 

On  the  15th  of  March  I  was  joined  and  assisted  in  these  labors  by  Mr.  St.  John, 
whom  I  had  previously  appointed  Assistant. 

The  opening  of  spring  being  later  than  usual,  no  field  -  work  was[done  until  the 
16th  of  April.  Intending  to  devote  the  greater  part  of  the  year's  labor  to  the 
investigation  of  our  resources  for  fuel,  this  work  was  commenced  on  that  day  in. 
Mahaska  county,  and  continued  until  the  6th  of  May,  embracing  the  examination 
of  the  coal  deposits  of  the  greater  part  of  the  counties  of  Mahaska,  Monroe,  Jef- 
ferson and  part  of  Wapello. 

It  being  then  necessary  to  commence  field-work  in  the  western  part  of  the 
State  where  it  was  left  at  the  close  of  the  previous  season,  preparation  was  made 
to  proceed  thither  with  the  appropriate  outfit.  At  this  time  I  received  a  proposi- 
tion from  the  eminent  naturalists,  Mr.  F.  B.  Meek  and  Dr.  Theodore  Gili,  both  of 
the  Smithsonian  Institution,  and  both  also  connected  with  the  United  States  Geo- 
logical Survey  of  Nebraska,  to  accompany  me  across  our  State  to  Nebraska, 
review  on  the  way  a  part  of  my  last  season's  field  -  work,  and  meet  Dr.  F.  V. 
Hayden,  Director  of  the  Nebraska  Survey,  at  Nebraska  City,  to  compare  notes, 
11 


82  REPORT  OF  STATE  GEOLOGIST. 

and  if  possible,  to  arrive  at  some  estimate  of  the  depth  at  which  the  equivalents  of 
the  productive  coal  -  measures  lie  beneath  the  unproductive  strata  exposed  along 
the  Missouri  river.  This  proposition  was  very  gladly  accepted,  especially  since 
the  first  -  named  gentleman  is  probably  better  acquainted  with  the  geology  of  the 
Missouri  river  region  than  any  other  person  living. 

Accordingly  upon  the  arrival  of  Mr.  Meek  and  Dr.  Gill  we  all  started  in  com- 
pany from  Iowa  City  on  the  22d  of  May,  and  arrived  in  Nebraska  City  on  the  6th 
of  June,  where  we  were  joined  by  Dr.  Hayden.  We  made  some  satisfactory  esti- 
mates of  the  aggregate  thickness  of  the  strata  exposed  within  the  limits  of  Iowa, 
but  judging  from  exposures  found  by  those  gentlemen  in  Nebraska  and  Missouri, 
it  seems  probable  that  there  is  a  thickening  of  the  strata  to  the  westward,  which 
the  Iowa  exposures  do  not  reveal,  so  that  the  equivalents  of  the  productive  coal 
strata  which  are  seen  along  the  Des  Moines  river,  lie  deeper  beneath  the  surface 
along  the  Missouri  river  than~would  have  been  inferred  by  an  examination  of 
Iowa  rocks  alone. 

Circumstances  obliged  me  to  suspend  the  investigation  of  this  important  sub- 
ject, but  I  still  think  it  reasonable  to  expect  to  find  coal  there  at  less  depth  than 
that  at  which  it  is  successfully  mined  in  some  other  parts  of  the  world. 

Parting  with  our  distinguished  friends  at  Council  Bluffs,  I  placed  Mr.  St.  John 
in  charge'  of  the  work  in  the  western  part  of  the  State,  assigning  to  him  for 
examination  that  portion  of  the  fourth,  fifth  and  sixth  tiers  of  counties  which  lies 
between  the  Missouri  and  Des  Moines  Rivers.  He  has  prosecuted  his  labors 
with  an  earnestness  and  zeal  which  can  only  be  inspired  by  a  love  of  science ; 
and  I  am  much  gratified  with  the  careful  and  able  manner  in  which  he  has  per- 
formed the  work  assigned  him.  I  respectfully  refer  you  to  his  report  of  progress 
to  me,  a  copy  of  which  is  herewith  submitted. 

Returing  to  Iowa  City,  I  accompanied  Prof.  Hinrichs  to  the  lead  -  mines  of 
Dubuque,  for  the  purpose  of  obtaining  material  and  information  in  regard  to  the 
mode  of  occurrence  of  those  ores,  and  the  methods  in  use  for  smelting  them. 
Although  our  stay  there  was  brief,  the  results  obtained  were  of  much  interest 
and  value. 

Resuming  the  fuel  investigations,  I  visited  all  the  operated  mines  in  the  counties 
of  Marion,  Wapello,  and  Van  Buren,  entering  and  examining  them  in  person,  and 
collecting  authentic  specimens  for  analysis. 

The  dryer  part  of  the  year  having  arrived,  I  made  the  necessary  preparation, 
and  in  the  latter  part  of  August  went  to  the  northern  part  of  the  State  to  examine 
the  country  for  peat,  directing  attention  principally  to  the  counties  of  Franklin, 
Wright,  Cerro  Gordo,  Hancock,  Worth,  Winnebago  and  Kossuth.  Very  large 
•quantities  of  this  valuable  fuel  exist  in  those  counties,  as  will  be  seen  by  refer- 
ence to  the  accompanying  letters. 

Those  examinations  were  continued  until  the  commencing  cold  weather  made 
it  hazardous  to  health,  when,  returning  by  way  of  Ft.  Dodge,  I  met  Mr.  St.  John 
there  with  his  camp,  and  together  we  spent  the  greater  part  of  two  weeks  in  the 
examination  and  mapping  of  the  large  gypsum  deposits  of  that  region. 
'  Pleasant  weather  continuing  later  than  usual  in  the  autumn,  both  Mr.  St.  John 


REPORT  OF  STATE  GEOLOGIST.  33 

and  myself  made  frequent  excursions  to  such  points  as  it  seemed  most  desirable 
to  examine.  Among  these  excursions  were  visits  to  important  peat  marshes  in  the 
counties  of  Mnscatine,  Linn  and  Clinton. 

The  usual  winter  work  is  now  in  progress,  the  results  of  which  promise  to  be 
of  increasing  interest  and  importance. 

I  beg  to  call  your  especial  attention  to  that  portion  of  the  report  of  the  chemist 
in  which  he  describes  his  methods  in  the  cheminal  analysis  of  coals,  which  he 
claims  to  be  new  and  eminently  practical. 

It  will  be  seen  thai  thus  far  the  work  of  the  survey  has  been  one  of  general 
reconnoissance  rather  than  of  detailed  field  -  investigation,  and  much  of  such 
general  work  yet  remains  to  be  done.  It  is  necessary  to  ascertain  the  geological 
structure  of  the  northwestern  portion  of  the  State,  and  to  make  farther  general 
examinations  in  the  coal  and  peat  regions.  After  this  the  details  of  our  geology 
should  be  fully  investigated  ;  especially  should  we  know  with  the  greatest  pos- 
sible accuracy  the  minute  geological  structure  of  our  coal  -  field,  for  upon  this 
knowledge  depends  the  intelligent  prosecution  of  mining  operations,  and  the 
consequent  avoidance  of  useless  expenditures  of  money  and  labor  which  vrili 
otherwise  be  sure  to  occur. 

Application  will  be  made  to  the  Twelfth  General  Assembly  for  a  sufficient 
appropriation  to  prosecute  the  work  to  a  successful  completion.     The  people 
everywhere  evince  a  lively  interest  in  the  success  of  the  survey,  and  their  uni- 
form kindness  to  its  officers  is  a  constant  source  of  gratification. 
Very  respectfully,  your  obedient  servant, 

CHARLES  A.  WHITE, 

State  Geologist. 

IOWA  CITY,  IOWA,  January  3,  1868. 


REPORT 

OF 

0.  H.  ST.  JOHN,  ASSISTANT  STATE  GEOLOGIST. 


To  DR.  C.  A.  WHITE,  State  Geologist: 

DEAR  MR:  In  accordance  wiih  your  instructions,  I  have  prepared  anrl  here- 
with submit  the  following  report  of  progress  of  the  field  -  investigations  un'ler  my 
charge  during  the  pust  season. 

In  compliance  with  your  instructions,  on  the  13th  of  June  last  I  began  the  pre- 
liminary survey  of  that  portion  of  the  State  comprising  the  fourth,  fifth  and,  in 
part,  the  sixth  tier  of  counties  lying  between  the  Des  Moines  and  Missouii  rivers. 
One  of  the  principal  objects  of  this  reconnaissance  was  to  ascertain  with  as  much 
accuracy  as  possible  in  so  short  time,  the  extent  and  chnracter  of  the  coal-field 
in  the  region  embraced  in  this  geological  district.  With  this  view,  I  made  a  jour- 
ney from  Council  Bluffs  up  the  valley  of  the  Missouri,  through  Harrison,  Monona 
and  Woodbury  counties  to  Sioux  City;  thence  we  passed  into  Crawford,  Shelby, 
Audubon,  Carroll  and  the  southern  portion  of  Sac  county.  The  above  enumerated 
counties,  with  the  exception  of  the  eastern  portion  of  Carroll  and  Sac  counties,  lie 
wholly  upon  the  Missouri  water -shed,  and  present  a  variety  of  physical  features 
which  one  would  hardly  suspect  from  a  casual  glance. 

Few  rock  exposures  occur  in  the  above-named  counties;  however,  there  are 
localities  which  supply  a  very  fciir  quality  of  stone  for  all  the  ordinarj'  porposes 
of  construction.  It  is  believed,  further,  thnt  the  manufacture  of  bricks  for  build- 
ing may  be  successfully  undertaken  in  almost  all  localities;  so  that,  after  all,  the 
scarcity  of  good  building-  stone  in  most  places  will  scarcely  be  noticed,  much  less 
can  it  ever  have  a  detrimental  influence  in  a  region  so  highly  favored  in  other 
respec' 3. 

In  the  region  about  Sioux  City  good  quarry  rock  is  obtained  from  the  lower 
members  of  the  cretaceous  deposits  there  exposed;  and  a  fair  quality  of  quick- 
lime is  manufactured  from  the  upper  chalky  beds  known  among  geologists  as  the 
Inoceramus  beds,  from  the  prevalence  of  this  shell  in  this  horizon.  In  the  imme- 
diate neighborhood  of  Sioux  City,  at  Sargent's  Bluffs,  and  at  Bruguicr's  Bluffs, 
and  above  on  the  Big  Sioux  River,  the  lower  members  of  the  cretaceous  are 
beautifully  exposed,  enabling  us  to  construct  a  complete  section  of  these  rocks  of 
above  one  hundred  and  thirty  feet  in  vertical  thickness,  and  which  were  studied 
in  as  much  detail  as  the  limited  time  at  my  disposal  would  permit.  On  the 
Boyer,  in  Harrison  county,  limited  exposures  of  strata  belonging  to  the  upper 


REPORT  OF  STATE  GEOLOGIST.  85 

coal  -measures  also  outcrop,  and  are  quarried  to  some  extent  in  the  vicinity  of 
Reel's  milks,  on  the  line  of  the  Chicago  &  Northwestern  Railway.  At  other 
points  in  Harrison  and  Monona  counties,  a  tufaceous  deposit  occurring  near  the 
base  of  the  "  bluff  formation,"  affords  a  durable  material  for  underpinning,  &c. 
Also  in  other  parts  of  these  counties  the  modified  drift  affords  limited  exposures 
of  a  more  or  less  coarse  ferruginous  conglomerate,  and  considerable  quantities 
of  lower  Silurian  limestone  boulders,  gneissoid  and  quartzose  boulders  are  met 
with,  particularly  upon  the  broad  upland  ridges  in  Ida,  Crawford,  Carroll  and 
Sac  counties. 

What  most  strikes  the  observer,  traveling  over  these  prairies,  is  the  unusual 
development  of  the  post  -  tertiary  deposits,  affording  him  one  of  the  most  inter- 
esting fields  of  research.  An  extensive  and  intimate  knowledge  of  these  later 
geological  deposits — comprising  the  glacial  drift,  the  sands  and  coarser  materials 
of  the  modified  drift,  the  fine  class  ot  the  bluff  and  finally  the  thick  accumula- 
tion of  soil  at  the  surface  —  would  have  the  most  direct  and  practical  bearing 
upon  the  development  of  the  agricultural  resources  not  only  of  this  particular 
section,  but  of  the  State  generally.  Throughout  this  region  the  soil  is  unsurpassed 
in  fertility,  and  the  very  numerous  water-  course  affords  a  pprfect  system  of  drain- 
age, thus  furnishing  a  satisfactory  explanation  for  the  remarkable  infrequency  or 
wet,  untillable  land. 

The  heavy  deposits  of  drift,  &c.,  which  so  extensively  prevail  and  to  a  great 
extent  conceal  from  view  the  underlying  rock  formations  in  the  counties  men- 
tioned in  brief  above,  offered  insurmountable  obstacles  to  the  successful  examin- 
ation of  the  carboniferous  strata  which  are  supposed  to  underlie  a  large  portion 
of  that  section  of  the  country.  Therefore  it  became  a  matter  of  greatest  impor- 
tance to  explore  the  country  lying  to  the  eastward,  or  between  the  grand  divide 
and  the  Des  Moines  river,  that  the  necessary  duta  might  be  sought  by  means  of 
which  to  enable  us  to  arrive  at  some  satisfactory  conclusion  regarding  the  nature 
of  the  strata  in  the  region  to  the  westward.  Commencing  these  explorations  in 
Green  county,  I  first  made  a  tolerably  detailed  examination  of  the  valley  of  the 
North  Coon,  and  subsequently  its  two  principal  tributaries,  the  South  and  Middle 
Coon  rivers,  and  their  numerous  affluents  in  Guthrie,  Dallas  and  Polk  counties, 
The  first  exposure  ol  unequivocal  coal  -  measure  strata  is  found  in  the  south- 
eastern part  of  Green  county;  and  thence  along  the  North  Coon  to  the  confluence 
of  the  South  Coon,  the  bluffs  which  continuously  border  either  margin  of  the 
valley,  afford  quite  extensive  and  very  satisfactory  exposures  of  the  coal-meas- 
ures, consisting  of  sandstones,  arenaceous  and  argillaceous  shales,  occasional 
layers  of  limestone,  and  two  or  three  thin  beds  of  coal,  which  latter  are  being 
worked  at  numerous  points  in  the  valley. 

The  South  and  Middle  Coon  valleys  also  contributed  valuable  data.  In  the 
region  bordering  upon  the  lower  reaches  of  these  streams,  we  recognized  a  set  of 
beds  which  attain  a  thickness  of  about  two  hundred  feet,  and  which  hold  a  position 
intermediate  between  the  coal -bearing  strata,  of  the  Des  Moines  river  region 
and  the  upper  coal-measures,  which  latter  series  you  saw  admirably  defined 
during  your  investigations  the  first  year  of  the  survey  in  Madison  county  and 


86  REPORT  OP  STATE  GEOLOGIST. 

the  southeastern  portion  of  the  State.  This  middle  series  of  strata  is  composed 
of  thin  beds  of  sandstone,  sandy  shales  and  variegated  clays,  impure  limestones 
always  in  comparatively  thin  bands,  and  sometimes  wanting  wholly,  carbon- 
aceous shales  and  coal.  There  are  three  distinct  and  constant  coal  horizons, 
which  separate  or  sub  -  divide  the  lines  into  as  many  lithologically  well  -  marked 
groups.  But  the  palaeontological  characters  bind  the  whole  together,  as  it  was, 
and  indicate  a  nearer  alliance  to  the  lower  coal  -  measures  —  as  we  at  present  under- 
stand that  series  —  than  they  do  to  the  upper  measures,  from  which  latter  it  is  quite 
distinct  in  its  lithological  features  also.  The  three  beds  of  coal  above  mentioned 
are  mined  with  considerable  success  at  the  present  time  in  both  Guthrie  and 
Dallas  counties,  and  the  quality  of  the  coal  is  usually  excellent,  although 
the  beds  are  very  thin,  possessing  an  aggregate  thickness  not  above  four  feet. 
The  productive  or  lower  coal-measures  lie  beneath  at  variable  depths,  and  can 
be  reached,  doubtless,  by  ordinary  shafting  at  most  any  point  in  these  counties  at 
a  depth  of  two  hundred  to  three  hundred  feet,  and  in  valleys  at  a  much  less 
distance  below  the  surface.  Indeed,  at  Redfield,  in  Dallas  county,  where  a  bed 
of  coal  nearly  three  feet  thick,  which  outcrops  in  the  banks  of  the  Middle  Coon, 
and  is  overlaid  by  a  thickness  of  at  least  forty  -  five  feet  of  sandstone,  and  which, 
it  is  believed,  is  equivalent  to  the  coal  seen  at  Des  Moines.  This  bed  has,  there- 
fore, been  upraised  so  as  to  occupy  about  the  same  elevation  above  the  level  of 
the  Middle  Coon  at  Redfield  as  it  does  above  the  level  of  the  Des  Moiues  river  at 
the  Capital.  And  the  intervening  country  forms  a  broad,  shallow  synclinal,  the 
axis  of  which  has  apparently  a  northerly  and  southerly  direction.  Hence  it  is 
that  at  the  South  arid  North  Coon  rivers,  there  occur  beds  which  belong  pretty 
well  up  in  the  middle  series,  or  to  its  middle  groups  of  strata. 

As  we  ascend  all  three  of  the  Coon  rivers,  to  the  northward,  we  encounter 
sandstones  and  clays,  and  ferruginous  grits,  in  Guthrie,  Carroll  and  Greene 
counties,  the  equivalency  of  wtyich  have  as  yet  not  been  satisfactorily  determined. 
And  in  carrying  on  these  examinations  up  the  beautiful  little  valleys  of  the 
tributaries  of  the  South  Coon,  in  the  southern  portion  of  Guthrie  county,  the 
westward  dip  of  the  strata  has  brought  down  the  lower  members  of  the  upper 
coal  -  measures  almost  on  a  level  with  the  valley  of  Deer  creek ;  but  before  we 
have  gained  the  headwaters  of  Beaver  creek,  whose  course  is  nearly  parallel  with, 
and  only  two  or  three  miles  north  of  the  former  stream,  the  strata  have  again  been 
upraised,  so  that  in  the  vicinity  of  Mr.  Mann's  and  Mr.  Cleman's,  in  Townships 
78  and  79,  Rnnge  31,  W.,  we  are  again  brought  in  contact  with  familiar  horizons, 
long  since  recognized  at  Vanraeter's,  a  few  miles  above  the  mouth  of  South  Coon, 
and  also  near  Adel,  on  the  North  Coon,  &c.  We  need  no  more  conclusive  evidence 
to  prove  the  irregularly  and  gently  -  undulating  character  of  the  strata  in  this 
section.  The  most  easterly  indication  of  one  of  these  broadly  swelling  -  anticiuals, 
in  connection  with  the  middle  series  of  coal  -  measures,  is  seen  in  the  bluffs  which 
border  the  north  side  of  the  Coon  river,  a  few  miles  above  Des  Moines,  and  in  the 
region  to  the  southward,  in  Warren  county.  Beyond  this  line  of  outcrop  —  east- 
ward —  not  a  vestige  of  the  middle  series  has  thus  far  been  detected 

The  importance,  I  may  say  the  necessity,  of  a  thorough  and  well  -  sustained 


REPORT  OP  STATE  GEOLOGIST.  gf 

exploration  of  the  area  occupied  by  this  most  important  mineral  product  within 
our  borders,  must  be  apparent  to  every  intelligent  person;  for,  I  believe,  we  shall 
be  able,  when  once  the  details  of  the  structure  of  our  coal  •  measures  shall  haye 
been  fully  worked  out,  as  has  been  done  in  other  states,  to  estimate  the  depth  at 
which  a  certain  bed  of  coal  may  be  found  at  any  given  point,  with  almost  as  great 
accuracy  as  we  measure  up  the  bared  face  of  a  river  bluff  in  order  to  ascertain 
the  thickness  of  the  strata  therein  exposed.  However,  much  still  remains  to  be 
accomplished  in  this  section  of  the  State,  before  the  work  shall  have  attained  that 
degree  of  perfection  which  shall  contribute  largely  to  the  economic  interests  of 
the  State,  and  merit  the  commendation  of  the  public. 

During  the  summer  my  friend  Mr.  J.  A.  Allen,  of  the  Musuem  of  Comparative 
Zoology,  Cambridge,  joined  my  party,  with  the  view  of  studying  the  Natural 
History,  particularly  the  Ornithology  and  Botany  of  the  State  ;  and  to  this  end 
he  made  valuable  collections  of  objects  of  natural  history,  and  I  doubt  not  he  will 
cheerfully,  at  the  proper  time,  prepare  his  observations  in  a  form  which  shall 
receive  the  highest  approbation  of  our  people. 

It  would  be  superfluous  to  extol  the  merits  of  a  region  so  well  and  favorably 
known  already,  as  that  comprising  the  four  or  five  eastern  counties  of  the  district 
herein  mentioned.  And  it  is  with  grateful  acknowledgements  I  return  my  sincere 
thanks  for  the  many  courtesies  my  party  received  at  the  hands  of  gentlemen  in  all 
parts  of  the  District. 

On  the  8th  of  October,  in  compliance  with  your  request,  I  discontinued  the  work 
in  the  counties  west  of  the  Des  Moines,  and  joined  you  on  the  10th,  at  Fort 
Dodge. 

Very  sincerely  and  respectfully, 

Your  obedient  servant, 

ORESTES  H.  ST.  JOHN. 

IOWA  CITY,  28th  Dec.,  1867. 


POPULAR  LETTERS 


OF 


THE  STATE  GEOLOGIST 


FOR    1867. 


12 


SURVEY  OF  COUNTIES. 


MAHASKA    COUNTY. 

The  principal  object  aimed  at  in  these  partial  examinations  of 
Mahaska,  Marion,  Monroe,  Wapello,  Jefferson  and  Van  Buren  coun- 
ties, was  to  place  before  the  public  reliable  information  in  relation 
to  the  mineral  resources  of  those  regions,  that  those  who  were  con- 
templating the  investment  of  capital  in  public  improvements,  manu- 
factories, or  other  enterprises,  might  know  the  advantages  our  State 
affords. 

The  largest  part  of  the  labor  performed  was  in  the  examination 
of  the  mines  and  outcrops  of  coal.  The  mines  were  all  entered  and 
examined  in  person,  specimens  from  different  parts  of  the  bed  col- 
lected for  analysis,  and  notes  taken  of  its  thickness  and  general 
character. 

The  St.  Louis  limestone  (sub  -  carboniferous)  is  found  cropping  out 
near  the  bottoms  of  the  valleys  of  the  Des  Moines  and  Skunk 
rivers,  as  well  as  some  of  their  tributaries.  Thus  it  is  known  that 
all  the  coal  of  the  county,  which  is  immense  in  quantity,  will  be 
found  in  the  high  lands  above  the  level,  at  least  of,  the  Des  Moines 
river,  because  it  is  useless  to  search  for  coal  beneath  the  limestone 
of  this  region ;  so  that  no  very  deep  mining  will  be  necessary  to 
reach  all  the  coal  that  the  county  contains.  That  which  is  now 
mined  is  reached  by  drifting  into  the  sides  of  the  valleys  of  the 
rivers,  creeks  and  ravines. 

In  the  north  part  of  the  county,  near  the  corifluence  of  Buck 
creek  with  the  north  branch  of  Skunk  river,  several  mines  have  been 
opened  in  a  four -foot  bed  of  coal,  and  many  more  may  without 
doubt  be  opened  there  whenever  the  demand  will  warrant  it.  Along 
Spring  creek,  from  near  its  confluence  with  South  Skunk  river  to 


92  REPORT  OF  STATE  GEOLOGIST. 

within  a  mile  or  two  of  Oskaloosa,  several  mines  have  been  opened, 
the  coal  of  which  ranges  from  four  to  upward  of  five  feet  in  thick- 
ness. On  this  creek  there  is  reason  to  believe  that  two  good  beds 
of  coal  exist,  the  one  beneath  the  other.  There  is  no  doubt  that 
large  quantities  of  coal  exist  along  this  creek,  which  may  be  readily 
mined  by  drifting  into  the  beds  at  their  out -crop  or  approach  to  the 
surface  on  each  side  of  the  valley. 

Around  the  outskirts  of  Oskaloosa  several  mines  were  visited  the 
beds  of  which  varied  from  three  and  a  half  to  five  and  a  half  feet  in 
thickness,  and  there  is  no  doubt  that  the  whole  city  is  underlaid  by 
a  good  bed  of  coal  at  a  moderate  depth.  At  Oskaloosa  Station,  on 
the  D.  Y.  Railroad,  two  and  a  half  miles  from  the  city,  the  thickest 
bed  of  coal  is  worked  yet  known  in  the  State.  It  measures  from 
five  to  nearly  eight  feet  thick  of  solid  and  good  coal.  Messrs. 
Roberts  &  Co.,  and  the  Iowa  Coal  Company  of  Keokuk,  both  have 
mines  in  operation  in  this  bed  near  the  station,  and  the  coal  in  their 
mines  will  probably  average  six  feet  in  thickness,  and  in  several 
places  it  reaches  seven  and  a  half  feet  thick.  They  are  conveniently 
ocated  in  relation  to  the  railroad,  having  car  -  tracks  laid  from  the 
railroad  platform  all  the  way  into  the  rooms  where  the  mines  are 
working.  The  coal  cars  are  drawn  all  the  way  into  the  mines  by  mules 
of  ordinary  size  without  difficulty.  Two  thousand  five  hundred 
bushels  daily  are  shipped  from  these  two  mines,  beside  a  consider- 
able quantity  of  coke,  of  good  quality,  which  they  have  lately 
commenced  preparing  for  shipment. 

Several  other  openings  have  been  made  within  a  few  miles  of 
these,  and  the  coal  found  to  be  as  thick  as  in  the  two  mines  just 
mentioned.  All  along  the  line  of  the  Des  Moines  Valley  Railroad, 
and  of  the  proposed  Iowa  Central  Railroad,  between  Oskaloosa  and 
Eddyville,  there  is  an  abundance  of  coal  which  may  be  readily  made 
accessible  for  shipment  upon  those  roads,  both  near  their  main  tracks, 
and  by  running  branch  tracks  up  the  branches  of  Muchekinock  creek, 
and  opening  mines  on  each  side  of  them  by  drifting  into  the  hill -sides. 

There  is  no  reasonable  doubt  that  the  whole  ridge  between  the 
creek  before  named  and  the  Des  Moines  river  is  underlaid  by  at 
least  one  good  bed  of  coal,  and  indeed  it  is  quite  as  conclusive  that 
the  higher  lands  of  the  greater  part  of  the  county  are  so  underlaid. 


REPORT  OF  STATE  GEOLOGIST.  93 

The  St.  Louis  limestone  furnishes  a  good  supply  of  building  -  rock 
and  lime,  the  brick -clays  are  of  average  quality  and  timber  is  more 
plentiful  than  is  usual  in  Iowa. 

MONROE  COUNTY. 

Along  all  the  creeks  and  streams  of  Monroe  county,  coal  is  to  be 
found,  but  the  lower  and  better  bed  is  reached  only  in  the  deeper 
creek  valleys,  because  the  county,  lying  upon  the  divide  between  the 
drainage  of  the  Mississippi  and  Missouri  rivers,  is  rather  higher  than 
those  adjoining  it,  and  the  material  above  the  coal  is  consequently 
thicker.  It  is  probable  that  large  quantities  of  coal  may  be  obtained 
by  sinking  shafts  down  from  the  high  lands  to  a  depth  not  exceeding 
two  hundred  feet.  Along  Miller's  creek  on  the  line  of  the  Iowa 
Central  Railroad  there  have  been  a  number  of  mines  opened,  and 
much  coal  may  doubtless  be  obtained  there  by  the  usual  process  of 
mining.  On  Bluff  creek,  from  four  to  six  miles  northward  from 
Albia,  several  mines  are  opened,  and  many  more  may  be.  On  Cedar 
creek,  in  the  northwestern  part  of  the  county  there  is  a  bed  of  coal 
exposed  in  the  bed  of  the  creek  which  has  been  found  to  be  nearly 
seven  feet  thick  at  that  point. 

On  Coal  creek,  three  miles  westward  from  Albia,  a  bed  of  coal 
only  thirty  inches  thick  but  of  excellent  quality  is  worked.  At  this 
mine,  upon  the  clay  floor  of  an  abandoned  opening  a  quantity  of  an 
efflorescent  astringent  substance  was  found  which  the  chemist  reports 
to  be  native  alum.  Standing  in  little  pools  around  the  mouth  of 
the  mine,  and  more  particularly  near  a  mine  on  Bluff  Creek  in  the 
north  part  of  the  county,  a  deep  -red  colored  water  is  found.  This 
the  chemist  reports  to  be  a  solution  of  the  per  -  sulphate  of  iron, 
with  sulphuric  acid  in  excess,  as  well  as  a  little  free  phosphoric  acid. 
On  the  line  of  the  Burlington  and  Missouri  River  Railroad,  near 
Chillicothe,  along  Avery's  creek  in  the  east  part  of  the  county,  Mil- 
ler's creek  in  the  northeastern  part,  and  along  Cedar  creek  in  the 
north  western  part,  this  lower  and  thicker  bed  of  coal  has  been 
worked,  affording  an  abundance  of  good  coal.  The  upper  and 
thinner  bed,  from  two  three  feet  in  thickness  is  opened  at  numerous 
localities  along  the  valleys  of  the  smaller  streams  in  varous  parts  of 
the  county,  particularly  in  the  vicinity  of  Albia.  The  quality  of 


94  KEPORT  OF  STATE  GEOLOGIST. 

this  upper  bed  of  coal  is  equal  to  that  of  the  lower  bed,  which  is 
worked  in  the  creek  valleys  before  referred  to.  The  sub  -  carbon- 
iferous limestone  is  found  near  the  moutl,!  of  Miller's  creek,  at  which 
point  alone  it  has  been  seen  within  the  county,  the  other  streams,  so 
far  as  known,  not  having  cut  their  valleys  down  so  deeply  as  to 
expose  it. 

Along  many  of  the  creeks  of  this  county  there  are  exposures  of 
sandstone  which  furnish  a  very  good  material  for  common  masonry, 
it  being  harder  and  firmer  than  the  coal  -  measure  sandstone  usually 
is. 

The  limestone  referred  to,  without  doubt  extends  beneath  the 
whole  county,  forming  the  floor  of  the  coal  -  measures,  and  if  this 
limestone  is  reached  in  boring  or  digging  for  coal,  the  work  should 
be  stopped,  for  there  is  no  hope  of  finding  coal  beneath  it. 

Timber  is  sufficiently  abundant  in  Monroe  county  to  furnish  fuel 
for  its  inhabitants,  even  if  they  had  no  coal,  and  the  abundance  of 
the  latter  fuel  will  always  keep  the  former  at  a  reasonable  price  for 
those  who  prefer  to  use  it. 

JEFFERSON  COUNTY. 

Jeiferson  county  has  been  known  longer  perhaps  than  any  other 
county  in  the  State  as  a  coal  region,  and  many  years  before  any 
railroad  had  reached  Iowa,  Fairfield  coal  was  carried  in  wagons  to 
the  Mississippi  river  towns,  and  was  in  high  repute  among  black- 
smiths. 

The  Burlington  &  Missouri  River  Railroad  has  since  been  built 
near  these  mines,  which  are  now  worked  by  two  parties,  Mr.  Heron 
and  Mr.  Richardson,  who  ship  the  greater  part  of  their  coal  to  Bur- 
lington. 

At  Coalport,  ten  miles  eastward  from  Fairfield  and  on  the  line  of 
the  same  railroad,  a  four -foot  bed  of  coal  is  worked  by  Messrs. 
Brown  &  Co.,  from  which  large  quantities  of  coal  are  also  shipped 
to  Burlington  and  intermediate  points.  These  mines  are  nearly  a 
mile  to  the  north  of  the  railroad,  and  the  coal  is  brought  to  it  on  a 
wooden  side-track.  There  is  good  reason  to  believe  that  the  land 
between  these  mines  and  the  railroad,  as  well  as  the  land  adjoining 
these  tracts,  is  underlaid  by  as  good  a  bed  of  coal  as  that  which 


REPORT  OF  STATE  GEOLOGIST.  95 

Brown  &  Co.  are  now  working ;  so  that  considerable  supplies  may  be 
expected  here  in  the  future  for  shipment  and  local  use.  No  statis- 
tics of  the  amount  of  coal  shipped  from  the  mines  of  this  county  on. 
the  Burlington  &  Missouri  River  Railroad  have  been  obtained,  but 
this  trade  is  one  of  considerable  importance. 

From  six  to  eight  miles  northward  ficom  Fairfield,  on  Walnut 
creek,  there  have  been  quite  a  number  of  mines  opened  in  a  four- 
foot  bed  of  coal,  and  many  more  may  be  opened  there  whenever  the 
demand  will  warrant  it. 

There  is  so  little  demand  for  coal  from  these  Walnut  creek  mines, 
except  in  winter,  that  only  one  was  found  in  operation.  It  is  owned 
and  worked  by  Mr.  Shaw,  who  was  conducting  the  work  in  a  very 
creditable  manner,  and  he  will  soon  be  able  to  supply  a  large 
amount  of  coal. 

Along  Cedar  creek,  a  few  miles  southward  and  southwestward 
from  Fairfield,  several  mines  have  been  opened  and  many  more  may 
doubtless  be  opened  along  the  creek  for  several  miles.  Messrs. 
Young  &  Stubbs  have  a  good  mine  in  operation  four  miles  south  of 
Fairfield,  in  a  bed  which  measures  from  three  and  a  half  to  nearly 
four  feet  thick.  There  is  also  another  bed  of  coal  overlying  the 
main  one  almost  twenty  feet.  This  bed  being  a  little  less  than  two 
feet  thick  is  thought  to  be  unprofitable  to  work  in  view  of  the 
abundance  of  coal  in  the  county.  It  may  be  that  this  bed  will  be 
found  of  profitable  thickness  elsewhere  ;  indeed  it  is  not  improbable 
that  the  mine  worked  by  Messrs.  Heron  &  Richardson,  may  prove 
to  be  in  the  same.  If  so,  it  is  probable  that  another  bed  exists 
beneath  it.  At  Read's  mill,  three  miles  southwestward  from  Fair- 
field,  a  good  mine  is  in  operation,  and  the  coal  is  taken  out  from  the 
pit  by  the  machinery  of  the  mill.  Along  Walnut  creek  in  the 
northern  part  of  the  county  there  have  been  a  number  of  mines  open- 
ed in  a  four  -  foot  bed,  and  many  more  may  be  opened  there  when 
the  demand  will  warrant  it. 

Our  coal  region  needs  long  and  careful  study  before  any  definite 
estimate  can  be  made  of  its  productiveness,  but  the  following  are 
some  of  the  conclusions  arrived  at  after  the  limited  examinations  thus 
far  made.  The  larger  streams  have  generally  cut  their  valleys  down 


95  REPORT  OF  STATE  GEOLOGIST. 

to  the  limestone  which  forms  the  floor  of  the  coal  -  measures,  beneath 
which  no  coal  may  be  expected.  Thus  no  very  deep  mining  will  be 
necessary  in  the  region  named.  The  larger  streams  have  cut  down 
their  valleys  to,  and  through  the  coal  beds,  and  nearly  all  the  mining 
is  now  done  by  drifting  into  their  edges  from  the  side  of  the  valleys. 
There  is  no  doubt  that  the  coal  -  beds  are  continuous  beneath  the 
higher  lands,  and  that  they  may  be  reached  by  the  more  expensive 
method  of  shaft  -  mining  whenever  the  demand  will  warrant  it. 

The  beds  of  coal  lie  so  nearly  horizontal  beneath,  and  irrespective 
of  the  general  surface,  that  very  safe  calculations  may  be  made  in 
the  vicinity  of  those  worked  upon  opening  other  mines  at  about  the 
same  level  in  the  neighboring  slopes. 

A  little  below  Read's  mill,  on  land  of  Col.  Thompson,  there  is  a 
good  quarry  of  limestone  from  which  some  large  and  excellent  stone 
have  been  taken  as  may  be  seen  in  the  basement  wall  of  the  new 
building  for  the  High  School  in  Fairfield.  Similar  stone  are  also 
found  in  the  northeastern  part  of  the  county,  but  there  are 
comparatively  few  exposures  of  it.  This  is  the  limestone  before 
mentioned  which  forms  the  floor  of  the  coal  -  measures,  and  conse- 
quently it  is  useless  to  seek  for  coal  beneath  it ;  and  if  in  the  future 
sinking  of  shafts  for  coal,  this  limestone  should  be  reached,  the 
work  should  be  discontinued. 

Overlying  the  coal  at  the  mine  of  Messrs.  Young  &  Stubbs,  as  well 
as  elsewhere  in  the  county,  is  a  deposit  of  soft  sandstone,  some 
twenty  feet  in  thickness.  Most  persons  would  pronounce  it  to  be 
too  soft  for  use,  but  the  former  gentleman  has  an  out  -  house  built  of 
it  which  has  stood  unchanged  for  a  number  of  years,  and  the  hard- 
ness of  the  stone  has  much  increased  upon  exposure.  It  will  doubt- 
less serve  a  good  purpose  in  the  more  inexpensive  buildings,  for 
which  the  ease  with  which  it  is  worked  recommends  it. 

Fuel  is  so  abundant  in  this  county  that  there  is  good  reason  to 
believe  that  timber  is  now  growing  faster  than  it  is  being  used.  The 
excellence  of  the  soil  is  too  well  known  to  need  commendation  from 
me,  and  there  is  hardly  one  of  the  natural  resources  which  the  county 
does  not  contain. 


REPORT  OF  STATE  GEOLOGIST.  Q7 

DUBUQUE  LEAD  MINES. 

A  short  visit  was  made  to  these  mines  in  July,  for  the  purpose  of 
collecting  data  and  material  to  supply  deficiencies  in  our  means  for 
investigating  their  mineralogy,  and  the  methods  of  smelting  the  lead 
ores';  and  in  some  respects  we  were  quite  successful. 

Some  of  these  results  have  now  a  definite,  practical  value,  but 
others  are,  at  present,  only  interesting  scientific  facts,  yet  we  do  not 
know  how  soon  they  may  assume  practical  importance.  Among 
the  interesting  facts  which  we  obtained  there,  are  several  that  have 
long  been  known  to  the  miners,  but  have  never  before  been  pub- 
lished to  the  world.  We  are  apt  to  forget  that  scientific  knowledge 
is  only  the  knowledge  of  the  few  collected,  arranged,  systematized 
and  published  for  the  benefit  of  all ;  and  that  the  knowledge  of  the 
miner  differs  from  that  of  the  mineralogist  only  in  degree,  not  in 
kind. 

Capt.  Thomas  Levin,  an  old  and  experienced  miner  of  Dubuque, 
who  furnished  much  valuable  information  for  the  former  Geological 
Report,  also  first  called  our  attention  to  the  well  -  marked  physical 
difference  between  the  lead  ore  of  the  east  -and -west  and  the  north- 
and  -  south  lodes.  This  difference  is  constant,  easily  recognized  by 
any  person  after  his  attention  has  been  called  to  it ;  and  the  fact  is 
a  very  interesting  one,  yet  it  has  never  appeared  in  print  before,  so 
far  as  we  are  aware.  Prof.  Hinrichs  is  giving  this  matter  its  merited 
attention,  and  hopes  to  derive  some  hints  from  it  concerning  the 
relative  difference  in  the  age  of  the  two  systems  of  crevices  or  lodes. 

Mr.  R.  Simpson,  of  Rock  Dale  Smelting  Works,  also  called  our 
attention  to  a  grey  substance  in  the  ore  obtained  from  a  limited  part 
of  one  of  the  mines  near  Dubuque,  which  he  finds  to  greatly  retard 
the  process  of  smelting,  and  to  diminish  the  product  of  lead.  We 
subsequently  obtained  good  specimens  of  this  ore  at  the  mine,  and 
the  Professor  has  already  made  analyses  of  the  substance  referred 
to,  which  he  finds  to  be  carbonate  of  lead  —  the  same  in  composition 
as  the  grey  substance  often  found  coating  the  common  ore.  In  this 
case,  however,  it  is  disseminated  throughout  the  mass  of  the  ore,  the 
small  cavities  of  which  are  often  filled  with  crystals  of  the  same 
substance.  The  carbonate  of  lead  when  obtained  in  sufficient 
13 


98  REPORT  OP  STATE  GEOLOGIST. 

quantities,  is  an  excellent  ore  if  smelted  in  a  suitable  manner,  but 
the  process  in  use  for  the  common  ore  (the  sulphuret)  is  not  suitable 
for  the  carbonate,  and  the  presence  of  the  latter  with  the  common 
ore,  seems  to  be  worse  than  useless.  This  arises  from  the  fact  that 
the  carbonate  fuses  at  a  much  lower  temperature  then  the  sulphuret, 
flowing  over  the  latter  ore  in  the  furnace,  and  prevents  the  compus- 
tion  of  the  sulphur  which  it  contains  and  the  consequent  liberation 
Of  the  lead.  The  only  modification  of  the  common  process  which  is 
now  in  use  for  the  smelting  of  this  mixed  ore,  which  he  would 
suggest,  is  to  add  small  quantities  of  crushed  charcoal  at  frequent 
intervals  during  the  smelting ;  and  even  this  he  thinks  of  doubtful 
value. 

It  seems  improbable  that  large  quantities  of  these  mixed 'ores  will 
be  obtained,  and  furthermore  it  is  reasonable  to  expect  that  the 
"  grey  slag  "  obtained  in  smelting  it  will  contain  more  than  the  usual 
quantity  of  "  slag  lead  "  which  will  be  saved  by  the  second  smelting, 
and  the  aggregate  product  may  thus  not  fall  so  far  short  as  the 
diminished  product  of  the  first  smelting  would  seem  to  indicate. 

From  the  smelting  works  before  mentioned,  we  obtained  specimens 
illustrating  every  stage  of  the  process  of  washing  and  smelting, 
including  the  sediment  from  the  troughs,  the  different  slags  from  the 
furnace,  and  both  "  soft"  and  lt  slag"  lead. 

We  also  obtained  specimens  of  quite  a  number  of  other  mineral  * 
substances  which  are  usually  associated  with  lead  ore.  From  these, 
and  from  examinations  of  the  cabinets  of  several  citizens  of 
Dubuque,  Professor  Hinrichs  was  able  to  make  out  the  order  of 
occurrence  of  nearly  a  dozen  different  minerals ;  or,  to  be  more 
explicit,  it  is  known  for  instance  that  a  certain  mineral  is  found  in  a 
crystalized  form  upon  the  surface  of  the  rock,  and  that  upon  the 
former,  crystals  of  another  mineral  will  be  found,  and  still  others 
upon  the  last,  &c.  It  is  this  order  of  occurrence  of  the  different 
minerals  which  is  in  part  engaging  the  Professor's  attention. 

It  was  also  our  intention  to  obtain  statistical  information  in  rela- 
tion to  the  present  and  past  product  of  the  mines,  but  we  found  that 
perfectly  reliable  statistics  of  this  kind  were  very  difficult  to  obtain. 
Indeed  the  oldest  and  best  informed  mining  and  smelting  proprietors 


REPORT  OF  STATE  GEOLOGIST.  99 

were  .slow  to  give  a  definite  opinion  upon  this  subject,  although  they 
were  very  willing  to  comply  with  our  wishes  in  this  respect  as  far  as 
possible.  From  conversation  with  these  gentlemen  I  obtained  the 
following  impressions,  namely :  that  l^ad -mining  is  now  in  a  toler- 
ably prosperous  condition,  but  there  were  times  in  its  early  history 
when  more  ore  was  raised  per  man  than  now.  The  increased  price 
of  lead  makes  mining  as  profitable  now  as  it  ever  was,  although' it 
requires  a  greater  proportion  of  labor  and  skill  to  obtain  the  ore 
than  formerly. 

Little  or  no  change  has  taken  place  in  the  methods  of  either  min- 
ing or  smelting  during  the  past  twenty  years,  except  the  projected 
drainage  of  the  mines  by  means  of  adit  levels. 

An  enterprise  of  this  kind  has  been  a  couple  of  years  in  progress 
by  a  New  York  company,  and  promises  to  be  very  successful.  A 
large  area  will  be  drained  by  :this  level  when  completed,  which  expe- 
rienced miners  believe  will  yield  large  quantities  of  lead  ore,  now 
inaccessible  on  account  of  the  water.  Should  this  enterprise  succeed, 
there  are  other  regions  near  Dubuque  which  may  be  drained  in  the 
same  manner  with  equally  good  prospects  of  success.  A  new  era  in 
the  history  of  Iowa  lead  -  mining  evidently  depends  upon  the  success 
or  failure  of  the  company  now  operating. 

Up  to  the  present  time  there  are  no  indications  that  deeper  mining 
will  be  profitable,  or  indeed  in  any  degree  productive  in  this  region. 
The  thickness  of  the  Galena  limestone  in  the  vicinity  of  Dubuque  is 
about  two  hundred  and  fifty  feet,  and  the  principal  portion  of  the 
lead  ore  is  found  above  the  middle  of  it,  very  little  being  found  near 
its  base  or  top.  The  only  exception  at  present  known,  is  shown  in 
an  opening  recently  made  a  short  distance  from  the  city  by  Messrs. 
McCraney  &  Hickok.  Here  these  gentlemen  have  found  a  lead- 
bearing  crevice  in  the  extreme  upper  part  of  the  Galena  limestone, 
which  has  no  cap  -  rock,  the  shales  of  the  so  -  called  Hudson  river 
group  lying  immediately  upon  the  top  of  the  fissure.  What  the 
extent  of  this  deposit  of  ore  is,  remains  to  be  proven,  as  it  had  been 
opened  only  a  few  days  at  the  time  of  our  visit.  Upon  some  speci- 
mens of  lead  and  zinc  ores  thrown  out  from  this  mine,  and  also  some 
presented  to  us  by  the  proprietors,  we  found  numerous- small  crys- 
tals of  native  sulphur.  Sulphur  in  the  water  of  springs  is  of  course 


100  KEPORT  OF  STATE  GEOLOGIST.. 

well  known,  but  we  believe  this  is  the  £rst  discovery  of  native  crys- 
talized  sulphur  yet  found  in  America,  and  its  occurrence  here  is  also 
somewhat  at  variance  with  opinions  which  have  been  entertained 
concerning  the  occurrence  of  sulphur  in  nature.  Science  is  pro- 
gressive, and  why  should  not  Iowa  contribute  her  share  to  its  pro- 


gress ? 


MARION  COUNTY. 


Every  coal  mine  in  this  county  which  it  was  possible  to  enter,  was 
visited  in  person,  although  to  accomplish  this  it  was  not  unfrequently 
necessary  to  wade  in  almost  ice-cold  water,  which  collects  in  the 
mines  when  they  are  not  vrorked.  This  is  the  condition  of  the 
majority  of  them  during  the  summer  months,  at  which  time  there  is 
little  demand  for  coal,  there  being  at  present  no  railroad  through 
that  portion  of  this  county  which  contains  the  largest  amount.  The 
first  mines  visited  were  those  of  Messrs.  Roberts,  Fisher  and  Barnes, 
near  Otley  station,  on  the  Des  Moines  Valley  Railroad,  about  seven 
miles  westward  from  Pella.  They  are  situated  on  the  upper  branches 
of  a  creek  which  empties  into  the  Des  Moines  river,  the  two  former 
on  section  twenty  -  eight,  township  seventy  -  seven,  range  nineteen, 
and  the  latter  on  section  twenty  -  one,  township  seventy  -  seven,  range 
nineteen.  The  thickness  of  the  coal  in  the  mines  of  Messrs.  Rob- 
erts and  Fisher,  is  from  five  to  six  feet.  That  of  Mr.  Barnes'  mine 
is  four  feet  thick  ;  and  being  evidently  in  the  same  bed  and  nearer 
the  depot  than  the  others,  it  has  been  suggested  that  the  coal  prob- 
ably thins  out  in  that  direction,  and  that  it  would  not  be  reached  by 
sinking  a  shaft  at  the  depot;  but  since  coal,  and  probably  the  same 
bed,  has  been  discovered  three  feet  thick  several  miles  beyond  thfe 
depot  in  the  same  direction,  there  appears  to  be  no  good  reason  why 
it  should  not  be  found  of  profitable  thickness  by  sinking  a  shaft  at 
that  point.  There  is  evidently  a  large  amount  of  coal  in  that  part 
of  the  county,  a  small  portion  only  of  which  has  been  fortunately 
exposed  by  the  erosion  of  the  creek  valley  before  mentioned.  Mr. 
Nossaman,  four  miles  southward  from  Pella,  has  opened  a  three  -  foot 
bed  of  coal  near  the  left  bank  of  the  Des  Moines  river,  which,  with 
those  before  mentioned,  are  the  only  ones  visited  on  the  east  side  of 
the  river  in  this  county.  At  Coalport,  some  four  or  five  miles  from 


REPORT  OP  STATE  GEOLOGIST. 

Pella,  Messrs.  Bosquet  &  Thompson  havtf'tfp'emSstf  a'mffie  in  the  face 
of  the  bluff  immediately  upon  the^rl^frt  W'k^of'llte'  tfces ;  Mujnes 
river,  the  coal  of  which  measures  fro'm  sixjt6  'se>en/fe"etjin  fhldktfess. 
There  is  a  band  of  cannel  coal  of  several  inches  in  thickness  associ- 
ated with  the  bituminous  coal  of  this  mine,  but  which  the  water  pre- 
vented me  from  seeing  at  the  time  it  was  visited.  This  bed  of  coal 
appears  in  the  face  of  the  bluff  as  a  broad  black  band ;  and  about  ten 
feet  beneath  it  is  a  similar  band  about  two  feet  wide,  which  repre- 
sents another  bed  of  coal  of  that  thickness.  Making  Knoxville  a 
point  from  which  to  work  up  the  west  side  of  the  river,  the  mine 
next  visited  was  that  of  Mr.  O'Neal,  about  two  miles  north  of  town, 
on  section  nineteen,  township  seventy  -  seven,  range  nineteen.  This 
consists  of  two  beds  of  coal,  each  about  two  feet  thick,  with  a  bed 
of  shale  between  them  of  similar  thickness.  The  evidence  that  these 
are  two  distinct  beds  of  coal  is  increased  by  the  fact  that  there  is 
much  difference  in  the  quality  of  each  ;  that  of  the  upper  being  the 
best,  and  much  esteemed  by  blacksmiths.  Going  northward  from 
here  about  half  a  mile  on  the  Red  Rock  road,  we  see  in  the  face  of 
the  bluff,  composed  of  sandstone  and  sandy  shale,  immediately  upon 
the  right  bank  of  White  Breast  creek  and  near  the  mill,  another  bed 
of  coal  two  and  a  half  feet  thick.  This  last  named  bed  is  nearly  on 
a  level  with  the  mill-dam  there,  and  probably  represents  the  thick 
bed  of  other  parts  of  the  county.  The  depth  at  which  this  lies 
beneath  those  of  O'Neal's  mine  could  not  be  definitely  ascertained, 
but  it  is  probably  not  less  than  fifty  feet.  Going  southward,  imme- 
diately at  the  outskirts  of  town,  Mr.  Brobst  has  a  mine  in  operation 
which  measures  four  feet  thick,  and  the  same  bed  no  doubt  underlies 
the  whole  town  of  Knoxville. 

The  next  mines  seen  in  this  direction  are  upon  the  banks  of 
English  creek,  three  or  four  miles  fro'm  town.  The  coal  in  these 
mines  measures  from  three  to  four  feet  in  thickness.  And  the  coal 
is  exposed  at  frequent  intervals  along  the  hillsides  bordering  this 
creek,  until  they  merge  in  those  which  border  the  bottom  lands  of 
Des  Moines  river.  The  bed  of  coal  in  which  the  last  named  mines 
are  opened,  evidently  thickens  in  the  direction  of  the  course  of  the 
stream,  that  is,  to  the  eastward,  and  probably  also  to  the  southward. 
This  is  clearly  seen  in  the  vicinity  of  Bussing's  mill,  four  miles  east 


102  REPORT  OF  STATE  GEOLOGIST. 

of  town,  whetfe  it  '-hag  *  reached  a  thickness  in  some  places  of  seven 
feet/i  Ifemiiie^  TPbick  havp\been  opened  in  the  vicinity  of  this  mill, 
upon  '•EkrglisJi  ksreek  and  its  branches,  have  from  five  to  seven  feet  in 
thickness  of  coal.  At  the-  mines  owned  by  Messrs.  Sherman,  New- 
man and  Ferrin,  about  a  mile  southward  from  the  mill,  the  coal  is 
from  five  to  six  feet  thick,  and  about  fifteen  feet  beneath  this,  another 
bed  of  coal  is  seen  cropping  out  in  the  bed  of  the  small  creek,  which, 
however,  is  only  about  eighteen  inches  thick.  Quite  a  number  of 
mines  have  been  opened  in  the  hills  in  the  vicinity  of  this  mill,  the 
coal  of  which  is  usually  compact  in  most  of  them.  While  this 
character  renders  the  mining  of  it  a  little  more  difficult,  it  will  be 
more  valuable  for  shipment  because  it  will  not  crumble  so  easily ; 
beside  which,  the  more  dense  the  coal  is  the  more  heating  power  it 
possesses  if  it  is  pure  coal,  which  this  seems  to  be.  When  an  east 
and  west  railroad  is  built  through  this  county  it  will  probably  pass 
up  the  valley  of  this  creek,  when  the  coal  lands  there  will  be  very 
valuable,  and  the  supply  of  coal  for  shipment  will  be  immense. 
Numerous  points  along  White  Breast  creek  were  visited  where  coal 
had  been  mined,  which  indicated  that  the  supply  that  may  be 
obtained  along  that  stream  is  very  great.  A  bank  was  visited  some 
six  miles  southwestward  from  town,  near  this  creek,  from  which 
considerable  quantities  of  cannel  coal  are  said  to  have  been  taken, 
but  not  now  being  worked  it  had  unfortunately  fallen  in  so  that  only 
a  few  fragments  of  the  coal  could  be  obtained.  Although  coal  may 
doubtless  be  obtained  in  almost  any  part  of  the  county,  the  south- 
eastern quarter  of  it  is  pre  -  eminently  its  coal  region.  Perhaps, 
however,  this  is  only  apparently  so,  and  that  just  as  heavy  beds  of 
coal  exist  in  other  parts,  the  streams  of  which  have  not  cut  their 
valleys  deep  enough  to  expose  them  as  they  have  in  the  southeast- 
ern quarter,  which  will  be  presently  explained.  Along  the  hillsides 
which  skirt  the  North  and  South  Cedar  creeks  from  their  entrance 
into  the  county  to  where  they  unite  and  enter  the  bottom  land  of  the 
Des  Moines  river,  a  bed  of  coal  is  found  naturally  exposed  at 
frequent  intervals,  which  measures  from  five  to  seven  feet  in  thick- 
ness and  sometimes  more.  This  region  has  now  only  a  local  country 
market  for  its  coal,  so  that  little  more  is  yet  done  in  the  way  of 
mining  it,  than  to  dig  into  the  exposures  to  ascertain  its  thickness. 


REPORT  OF  STATE  GEOLOGIST.  1Q3 

The  thickest  bed  of  coal  found  there,  and  so  far  as  at  present 
known,  the  thickest  in  the  State,  measures  nearly  ten  feet  in 
perpendicular  thickness,  the  room  in  the  mine  being  higher  than 
many  of  the  rooms  of  our  dwellings.  This  mine  belongs  to  Mr. 
Jacob  Kline,  and  is  located  on  section  twenty  -  nine,  township 
seventy  -  four,  range  eighteen.  About  three  feet  from  the  top 
of  the  bed  of  coal  there  is  a  band  of  shale  a  couple  of  inches 
thick,  which  suggests  that  there  may  in  reality  be  two  separate 
beds  which  at  this  point  have  come  together. 

Marysville,  a  cosy -valley  village  which  has  been  built  up  by  an 
intelligent  and  industrious  community,  composed  principally  of 
Pennsylvanians,  since  most  of  our  maps  were  made,  is  situated  upon 
the  same  section.  Here  two  other  mines  are  opened  and  worked 
with  only  sufficient  force  to  supply  the  neighborhood  and  the  mills  of 
the  village.  The  first  is  owned  by  Mr.  John  Yenser,  and  the  other 
by  Mr.  D.  F.  Leiby.  A  couple  of  miles  below  the  village  Mr.  Gr.  H. 
demons  has  made  an  opening  in  the  same  bed.  The  coal  at  Marys- 
ville is  seen  in  the  face  of  the  bluff  on  the  right  bank  of  the  creek 
in  much  the  same  position  as  that  at  Coalport  before  mentioned ;  and 
a  similar  bluff  exposure  of  the  same  bed  is  seen  on  the  right  bank 
of  North  Cedar  creek,  on  land  belonging  to  Mr.  A.  P.  Chambers, 
section  sixteen,  township  seventy  -  four,  range  eighteen.  Farther 
down  the  creek,  on  land  of  A.  B.  Lyman,  Esq.,  there 
are  other  exposures  of  coal,  but  the  want  of  a  market  has 
prevented  them  from  being  worked.  Beside  these  and  numerous 
other  exposures  of  coal  along  the  two  Cedar  creeks  there  are 
many  others  along  the  hillsides  which  skirt  the  bottom  land  of 
the  Des  Moines  river.  Mr.  Daniel  Sherwood,  a  couple  of  miles 
southward  from  Attica,  is  working  one  upon  a  branch  of  North 
Cedar,  evidently  in  the  same  bed  as  the  others  just  mentioned. 

Although  that  member  of  the  sub  -  carboniferous  limestone  series, 
known  among  geologists  as  the  "  St.  Louis  limestone  "  is  found  in 
the  bed  of,  and  skirting  the  Des  Moines  river  almost  all  the  way 
from  a  few  miles  below  the  state  capital  to  Keosauqua,  and  is  often 
a  very  good  building  -  rock,  yet  the  same  bed,  when  found  in  the 
vicinity  of  Pella  is  somewhat  different  in  texture  from  that  of  almost 
all  the  exposures  of  it  yet  seen.  At  other  localities,  although  often 


104  REPORT  OF  STATE  GEOLOGIST. 

in  distinct  and  massive  layers,  it  is  usually  very  compact  and  brittle, 
breaking  in  such  an  irregular  manner  that  it  is  dressed  with  great 
difficulty,  yet  in  all  cases  furnishing  a  superior  quality  of  lime.  That 
of  the  Pella  quarries  is  regularly  bedded,  and  is  not  only  wrought  with 
great  facility,  being  free  from  flinty  material,  but  is  evidently  very 
durable  as  well  as  of  a  pleasing  appearance  when  dressed.  The 
quarries  have  a  thickness  of  from  eight  to  ten  feet,  the  upper  half  of 
which  is  usually  in  rather  thin  layers,  which  are  valuable  for  lime 
and  all  the  purposes  of  common  masonry;  but  the  lower  half  is 
formed  of  the  excellent  material  referred  to,  which  may  be  quarried 
with  comparative  ease,  in  all  the  forms  and  sizes  usually  desired. 

Although  the  stone  varies  a  little  in  texture  and  appearance  at 
each  of  these  quarries,  there  is  abundant  evidence  that  they  are 
portions  of  the  same  continuous  beds5  which  also  underlie  the  inter- 
vening region,  although  covered  too  deeply  by  soil  and  drift  mate- 
rial to  be  accessible. 

The  texture  of  the  massive  layers  in  the  quarries  south  -  westward 
from  the  town  is  inclined  to  be  oolitic  —  a  term  used  to  indicate  a 
rock  composed  of  small  spherical  particles  resembling  the  roe  of 
fishes —  while  the  same  beds  two  and  a  half  miles  north  of  town,  four 
feet  in  thickness,  are  made  up  entirely  of  the  fossilized,  cast  -  off 
shells  of  a  minute  bivalve  crustacean.  (BeyricTiia  petrif actor.) 

A  mile  and  a  half  northward,  the  same  beds,  are  seen  in  the  quar- 
ries of  Mr.  Phillip  Mather,  and  there  present  a  dense,  fine  -  grained 
texture  of  excellent  quality  for  dressing,  and  of  a  lighter  grey  color 
than  the  others.  From  these  quarries,  beside  specimens  of  each 
variety  of  the  rock,  a  good  collection  also  of  the  fossils  which 
characterize  this  member  of  the  sub  -  carboniferous  limestone  series, 
were  obtained  to  add  to  the  State  Cabinet. 

Mr.  W.  Nossaman  has  some  excellent  quarries,  both  for  lime  and 
dressed  stone,  almost  four  miles  south  of  Pella.  His  coal  mine, 
before  mentioned,  is  only  a  few  rods  distant  from  his  quarries,  the  bed 
of  coal  lying  some  twenty  -  five  feet  above  the  limestone,  so  that  he 
runs  the  coal  from  his  mines  'to  his  lime  -  kilns  without  any  further 
transportation. 

The  limestone,  although  not  the  upper  member  of  the  full  series 
of  sub  -  carboniferous  strata,  is  yet  the  upper  member  of  that  series 


REPORT  OF  STATE  GEOLOGIST.  105 

in  our  own  State,  and  the  coal  -  measure  strata  throughout  the  Des 
Moines  Valley  are  found  resting  upon  it.  Consequently  it  is  useless 
to  look  for  coal  beneath  this  rock,  judging  from  all  the  experience 
which  geology  has  yet  furnished  us.  Throughout  the  greater  part 
of  Marion  county  however,  this  rock  lies  so  deep  beneath  the  surface 
as  to  give  space  between  it  and  the  surface  for  those  important 
deposits  of  coal  before  described.  The  sandstone  of  this  county 
belongs  to  the  coal  -  measures,  and  of  course  overlies  the  limestone. 
Much  of  it  is  soft,  at  least  when  first  taken  from  the  quarry,  yet  it 
hardens  considerably  when  exposed  for  a  short  time  to  the  atmos- 
phere. 

There  are,  however,  large  quantities  of  this  sandstone  that  is  hard 
enough  for  any  purpose  as  a  building  material.  The  principal 
of  these  firm  exposures  of  sandstone  are  found  at,  and  near 
the  village  of  Red  Rock,  on  the  Des  Moines  river,  although  sand- 
stone equally  good,  but  of  a  different  color,  is  found  in  various  parts 
of  the  county.  This  stone  at  Red  Rock  assumes  the  character  of 
a  clean  grit  sandstone,  most  of  which  is  of  a  bright  brick  -  red  color. 
The  exposure  here  is  a  bold  bluff,  reaching  a  height  of  about  seventy 
feet.  In  some  few  places  the  stone  appears  to  be  soft,  but  the 
greater  part  of  it  is  quite  uniform  in  hardness,  and  the  layers  so  mas- 
sive that  blocks  of  almost  any  desired  size  can  be  quarried.  Much 
of  this  stone  has  already  been  used  in  various  places,  and  a  part  of 
that  used  in  the  construction  of  the  State  Arsenal  was  obtained  from 
these  quarries.  On  the  opposite  side  of  the  river  valley  from  Red 
Rock  there  are  similar  bluffs  of  the  same  sandstone,  which  presents 
nearly  the  same  colors.  The  same  exposure  also  is  seen  in  a  gradu- 
ally diminishing  bluff  bordering  the  valley  along  several  miles  below 
Red  Rock. 

Some  large  and  small  concretionary  masses  of  what  geologists  call 
quartzite  were  found  at  Red  Rock  and  other  places  in  this  county, 
embedded  in,  and  forming  a  part  of  the  sandstone  -  deposit,  the  lines 
of  stratification  running  without  interruption  through  each,  showing 
that  the  quartzite  is  a  part  of  the  same  deposit.  To  produce  this 
change  of  sandstone  in  nature  it  was  once  supposed  that  great  heat 


106  REPORT  OF  STATE  GEOLOGIST. 

was  necessary;  but   we  have'  no  evidence  that  any  of  the  accessible 
strata  of  Iowa  have  been  altered  by  hea-t. 

The  limestone  before  described  doubtless  underlies  the  whole  of 
Marion  county,  but  only  appears  where  slight  undulations  have 
brought  it  up,  or  where  the  streams  have  cut  their  valleys  down 
to  it  through  the  coal  -  measure  strata.  The  coal  -  measures,  com- 
posed of  sandstone,  shale,  clay  and  coal,  lie  comformably  upon  this 
limestone,  and  follow  it  in  its  dips  and  undulations.  Upon  the  coal- 
measure  strata  rests  the  drift  material,  a  part  of  which  forms  the 
soil  and  sub  -  soil. 

The  original  horizontal  position  of  the  limestone  and  coal -measure 
rocks  has  been  but  slightly  changed  in  this  county,  and  are  quite 
independent  of  any  inequalities  of  the  present  surface  of  the  earth, 
because  those  inequalities  are  due  to  the  erosion  of  the  valleys  by 
the  streams  which  run  through  them,  thereby  cutting  down  through 
each  successive  stratum,  the  edge  of  every  one  of  which  would  be 
seen  in  the  sides  of  the  valleys  if  it  were  not  that  they  are  cov- 
ered by  the 'soft  material  derived  from  their  disintegration.  Thus 
we  find  exposures  of  coal  only  where  they  have  been  cut  through  in 
this  manner  by  the  streams,  and  thus  the  conclusion  is  perfectly 
legitimate  that  the  same  beds  of  coal  extend  continuously  beneath 
the  high  lands,  whose  edges  we  see  upon  each  side  in  the  valleys. 
The  question  often  arises  as  to  how  many  different  beds  of  coal  there 
are  in  this  county.  This  question  can  -not  be  answered  in  a  perfectly 
satisfactory  manner  until  the  whole  region  has  been  carefully  and 
minutely  examined,  which  will  be  a  work  requiring  far  longer  time 
to  accomplish  than  can  now  be  given  to  it. 

The  conclusion  arrived  at  from  the  partial  examination  thus  far 
made  is  that  there  are  in  Marion  county  at  least  three  separate  beds 
of  coal,  the  middle  one  of  which  is  much  the  most  important  and 
extensive.  The  others  seem  to  thin  entirely  out  in  some  places,  so 
that  it  is  doubtful  whether  they  would  all  be  pierced  by  a  boring 
made  at  any  one  point ;  yet  there  is  probably  no  point  upon  the  high 
lands  of  this  county  which  is  not  underlaid  by  more  or  less  coal.  To 
be*  a  little  more  explicit,  it  may  be  stated  that  the  double  bed  — 
counted  as  one  —  of  Mr.  O'Neal's,  is  regarded  as  the  highest,  and 


REPORT  OF  STATE  GEOLOGIST.  107 

that  the  thick  one  in  which  the  mines  of  Coalport,  English,  Cedar 
and  other  creeks  are  opened,  is  believed  to  be  the  second,  and  the 
thin  one  beneath  the  last  -named  bed,  as  seen  at  Coalport  and  also 
a  mile  south  of  Bussing's  mill,  would  consequently  be  the  third. 
The  first  occurs  apparently  above  the  principal  sandstone  horizon, 
and  the  second,  a  main  bed,  just  beneath  it.  This  horizon  does 
not  always  present  firm  exposures  of  sandstone,  as  at  Red  Rock, 
Eagle  Rock,  Bussing's  mill,  a  mile  above  Marysville,  &c.,  but  may 
be  seen  in  the  form  of  yellow  comminuted  sandy  shale,  upon  the 
sides  of  the  hills  in  many  places  —  more,  perhaps,  than  where  it 
appears  as  firm  rock.  Thus,  if  one  should  sink  a  shaft  with  a  view 
of  reaching  the  main  bed,  after  passing  through  the  upper  bed,  as 
Mr.  John  Gamble  has  done  in  digging  a  well  at  his  residence  just 
north  of  Knoxville,  where  he  found  it  four  feet  thick  at  a  depth  of 
thirty  feet,  he  would  then  pass  through  a  considerable  thickness  of 
either  sandstone  or  sandy  shale.  If  he  were  seeking  the  position  of 
that  bed  upon  the  hillside,  he  might  expect  to  find  it  near  the  base 
of  that  sandy  horizon,  whether  of  sandstone  or  sandy  shale.  The 
sub  -  carboniferous  limestone  before  mentioned  can  not  lie  very  deep 
beneath  any  part  of  the  county ;  consequently  no  very  deep  mining 
will  be  necessary  in  any  part  of  it.  It  is  thought  that  a  shaft  of  two 
hundred  feet  at  any  point  in  the  county  will  reach  all  the  coal  to  be 
found.  The  time  will  coine  when  it  will  pay  to  sink  such  shafts  from 
the  highlands  to  obtain  the  coal  from  the  extensive  beds -which  are 
thus  far  only  very  slightly  penetrated  from  their  edges. 

The  quality  of  the  coal  of  this  county  is  fully  equal  to  the  average 
of  Western  coal,  and  that  of  many  of  the  mines  is  in  excellent 
repute  among  blacksmiths  for  working  iron. 

Marion  is  one  of  the  best  supplied  counties  in  the  State  for 
timber.  Much  of -the  original  forest  yet  remain  along  the  streams, 
and  the  young  timber  is  growing  vigorously  wherever  it  is  allowed 
to  stand.  The  prairies  are  comparatively  small,  and  beautiful  groves 
of  native  trees  are  scattered  almost  everywhere,  giving  a  very 
pleasing  effect  to  the  landscape.  The  streams  being  numerous,  the 
county  is  well  watered,  besides  which,  wells  of  good  water  are 
easily  obtained  at  moderate  depth  almost  anywhere,  some  of  which 
have  penetrated  beds  of  coal.'  It  would  be  superfluous  to  add 


108  REPORT  OF  STATE  GEOLOGIST. 

anything  in   praise  of  the  fertilky  of  the  soil  to  those  who  see  the 
bountiful  harvest  which  is  now  everywhere  burthening  the  fields. 

WAPELLO  COUNTY. 

The  examination  of  this  county  was  commenced  in  the  western 
part,  on  the  south  side  of  the  Des  Moines  river,  and  the  first  mine 
visited  was  that  of  C.  Dudley  &  Company,  on  section  four,  seventy- 
two,  fifteen.  Judging  from  what  is  now  to  be  seen  of  this  mine  its 
coal  will  prove  to  be  unsurpassed  by  any  other  now  offered  in  the 
market,  and  these  gentlemen  will  soon  be  able  to  furnish  very  large 
quantities.  The  bed  is  four  feet  thick,  and  very  uniform  in  quality. 
They  are  now  constructing  a  tram  road  from  their  mine  to  the  track 
of  the  Burlington  and  Missouri  Railroad,  a  little  less  than  a  mile 
distant.  About  half  a  mile  southward,  from  this  mine  an  opening 
has  been  made  in  what  appears  to  be  the  samo  bed,  but  the  quality 
of  the  coal  now  obtained  is  poor,  and  I  fear  the  prospect  is  not 
flattering  that  it  will  improve  much  within  a  short  distance.  A 
quarter  of  a  mile  westward  of  Dudley  &  Company's  mine  an  opening 
in  the  same  bed  is  being  made  with  good  prospect  of  finding 
excellent  coal.  The  bed  in  which  the  last  named  opening  has  been 
made,  as  well  as  that  of  Dudley  &  Company,  is  the  second  in  the 
series,  as  may  be  seen  by  going  down  the  creek  a  few  rods,  where 
the  limestone  —  which,  as  said  in  previous  letters,  forms  the  floor 
of  the  coal-measures,  and  beneath  which  no  coal  need  be  sought 
for  —  is  found  in  the  bed  of  the  creek.  About  three~feet  above  this 
limestone  is  seen  a  bed  of  coal  which  is  here  only  about  one  and  a 
half  feet  thick,  and  which  is  of  course  the  lowest  in  the  series. 
Above  this  bed  of  coal  is  a  space  of  about  forty -five  feet,  the 
material  composing  which  is  partly  hidden  by  the  slope  of  the  hill ; 
and  upon  this  rests  the  four  -  foot  coal  bed  of  Dudley  &  Company's 
mine.  On  the  north  side  of  the  creek  (North  Avery)  a  little  more 
than  a  mile  from  the  last  named  mine,  Mr.  J.  G.  Heacock  has 
opened  one  in  a  four -foot  bed  of  coal,  but  since  the  before  mention- 
ed limestone  is  seen  exposed  in  the  slope  only  about  five  feet  beneath 
the  coal  there,  no  doubt  is  felt  that  this  is  the  lower  bed  of  coal,  and 
therefore  not  identical  with  that  of  the  mine  of  Dudley  £  Company, 
but  with  the  thin  one  which  lies  forty  -  five  feet  beneath  it.  Mr. 


REPORT  OF  STATE  GEOLOGIST. 

Heacock  has  only  just  opened  his  mine,  and , the  quality  does  not 
seem  to  be  as  good  as  some  others,  yet  it  will  no  doubt  make  good 
fuel  for  steam  purposes.  It  is  reasonable  to  suppose,  however,  that 
the  quality  will  somewhat  improve  as  the  mining  proceeds  beneath 
the  hill,  but  there  is  also  reason  to  believe  that  the  coal  of  the 
second  bed  will  be  found  to  be  better  than  that  of  the  first,  at  least 
in  this  part  of  the  county.  Going  down  the  river  valley  three  miles 
below  the  village  of  Chillicothe,  to  the  mines  of  Henry  Shock  & 
Company,  on  section  eight,  township  seventy  -  two,  range  fourteen, 
the  coal  was  found  to  be  of  good  quality,  and  the  bed  five  feet  thick. 
These  gentlemen  furnish  a  large  amount  of  coal  for  shipment  on  the 
B.  &  M.  Railroad.  About  a  quarter  of  a  mile  further  up  the  small 
creek  which  comes  into  the  Des  Moines  river  there,  and  upon  the 
same  section,  Mr.  David  C.  Evans  has  just  got  a  mine  into  good 
working  order  in  the  same  bed  of  coal,  which  here  also  measures  five 
feet  in  thickness,  and  the  quality  fully  equal  to  that  of  Shock  & 
Company.  There  is  no  doubt  that  the  high  lands  bordering  this 
creek  and  the  adjacent  high  lands  bordering  the  Des  Moines  river 
bottom  are  underlaid  by  as  good  coal  as  is  seen  in  the  mines  just 
mentioned. 

In  the  immediate  vicinity  of  Ottumwa  several  mines  have  been 
opened,  but  the  beds  are  rather  thin  and  the  quality  poorer  than  th'e 
coal  of  the  county  will  average,  although  they  furnish  a  considerable 
amount  of  good  coal.  The  first  and  second  beds  of  coal  are  repre- 
sented in  the  hills  at  Ottumwa,  but  yet  it  seems  probable  that  the 
principal  supplies  for  the  city  must  he  brought  from  mines  four  or 
five  miles  distant.  About  that  distance  to  the  northwestward  from 
the  city,  on  section  thirty  -  three,  to WL ship  seventy  -  three,  range 
fourteen,  Messrs.  Brown  &  Godfrey  have  some  mines  in  operation 
from  which  they  are  preparing  to  ship  large  quantities  of  coal.  Both 
the  D.  V.  and  B.  &  M.  Railroads  run  near  each  other  within  a  mile  of 
their  mines  which  will  give  them  unusual  advantages  in  shipping 
coal  to  various  markets  on  both  roads.  The  quality  of  their  coal  is 
good,  and  the  bed  measures  from  four  to  four  and  a  half  feet  thick. 
Northwestward  from  these  mines,  and  about  a  mile  southward  from 
Kirkville,  several  other  mines  have  been  opened,  all  apparently  in 


REPORT  OF  STATE  GEOLOGIST. 

the  same  bed.  Those  latterly  known  as  Smith's  mines  have  been  on 
fire  for  several  months,  probably  the  work  of  an  incendiary,  but  are 
now  nearly  extinguished.  The  coal  of  these  mines  has  long  been  in 
good  repute,  and  Mr.  Smith  will  soon  have  them  in  working  order 
again.  Mr.  Joshua  Marshall  has  a  good  five  -  foot  mine  in  good 
condition  on  section  seventeen,  township  seventy  -  three,  range 
fourteen,  and  has  a  good  local  market  for  his  coal.  In  the  immedi- 
ate vicinity  of  Eddyville  several  mines  are  worked  in  a  bed  which 
ranges  from  three  to  four  and  a  half  feet  in  thickness.  From  these 
mines  some  specimens  of  coal  were  obtained  as  fine  as  any  I  have 
seen  in  the  West.  An  exposure  of  cannel  coal  was  reported  to  exist 
in  the  immediate  bank  of  the  Des  Moines  river,  about  half  a  mile 
above  the  town,  but  the  river  was  too  high  at  the  time  of  my  visit  to 
see  it.  From  indications  observed  in  the  northwestern  quarter  of  the 
county  there  is  reason  to  believe  that  this  region  will  furnish  very 
large  quantities  of  excellent  coal  for  export,  which  may  be  readily 
run  down  to  the  railroads  by  branch  tracks  laid  along  the  numerous 
small  streams  which  empty  into  the  Des  Moines  river.  This  will 
make  Wapello  one  of  the  principal  exporting  coal  counties  of  the 
State;  indeed,  more  coal  is  now  shipped  upon  the  Burlington  & 
Missouri  Railroad  from  this  county  than  from  any  other  through 
which  it  passes. 

Thus  far  very  little  coal  has  been  found  in  the  southwestern  and 
northwestern  quarters  of  the  county,  but  in  the  former,  if  not  also 
in  the  latter,  it  is  probable  that  coal  may  be  found  at  a  moderate 
depth  beneath  the  surface,  but  down  to  which  the  valleys  of  the 
creeks,  being  small  ones,  have  not  been  cut,  as  has  been  the  case 
along  the  river  and  the  larger  creeks.  A  large  amount  of  coal, 
however,  is  found  in  the  southeastern  part  of  the  county,  the  princi- 
pal mine  of  which  is  worked  at  Alpine  Station,  on  the  D.  V.  Rail- 
road by  the  Alpine  Coal  Company,  under  the  direction  of  Mr. 

C.  J.  Love. 

This  mine  furnishes  large  quantities  of  coal  for  the  Keokuk 
market,  where  it  is  in  good  repute,  being  shipped  there  upon  the 

D.  Y.  Railroad.     The  bed  is  from  four  to  five  feet  thick,  and  since 
the  mine  was  opened  it  has  furnished  about  one  million  bushels  of 


REPORT  OF  STATE  GEOLOGIST.  ]Q ^ 

coal,  which  is  probably  more  than  the  product  up  to  this  time  of  any 
other  mine  in  the  State. 

The  St.  Louis  limestone  without  doubt  underlies  the  whole  of  this 
county  in  the  same  manner  that  it  underlies  those  described  in  the 
preceding  pages.  It  is  exposed  at  numerous  points  along  the  Des 
Homes  and  its  tributaries  at  and  above  Ottumwa.  It  furnishes 
excellent  material  for  lime,  and  also  good  building  rock,  much  of 
which  is  suitable  for  dressing. 

Below  Ottumwa  the  limestone  rapidly  dips  beneath,  so  that  the 
coal  -  measure  sandstone  is  seen  near  the  water's  edge,  a  mile  below 
town,  and  just  below  Alpine  station,  eight  or  nine  miles  from  Ottumwa, 
a  bed  of  coal  is  found  in  the  bed  of  the  river.  The  sandstone  referred 
to,  is  of  the  same  general  character  as  the  coal  -  measure  sandstone 
before  spoken  of,  but  it  is  not  quite  so  firm,  nor  so  uniform  in  quality 
as  that  obtained  at  Red  Rock.  It  will  hardly  be  used  where  good 
limestone  can  be  easily  obtained,  but  yet  much  of  it  will  answer  well 
the  purposes  of  common  masonry. 

Usually  the  strata  of  the  Iowa  coal  -  field,  as  well  as  the  underlying 
sub  -  carboniferous  limestone,  are  very  regular  and  undisturbed,  but 
commencing  a  little  above  Ottumwa  and  going  down  the  valley  there 
is  seen  to  be  considerable  evidence  of  disturbance  of  the  strata. 

This  disturbance  has  not  been  violent,  but  yet  sufficient  to  pass  the 
limestone  beneath  the  level  of  the  river  just  below  Ottumwa,  so  that 
it  does  not  appear  again  below  that  point  in  this  county.  At 
the  Alpine  mines  below  referred  to,  the  coal  and  its  associated  beds 
also  partake  of  the  disturbance  so  that  the  bed  of  coal  is  entirely  cut 
oft' at  one  place  within  the  mine,  by  what  seems  to  have  been  a  settling 
of  the  superincumbent  mass  in  longitudinal  folds,  the  folds  having  a 
general  direction  from  northeast  to  southwest.  A  number  of  these 
folds  have  been  met  with  in  the  mine,  depressing  the  roof,  but  only 
one  of  them  has  been  found  to  cut  the  coal  entirely  off.  Judging 
from  the  character  of  the  others,  the  miners  may  expect  to  find  the 
coal  again  after  passing  a  short  distance  through  the  material  which 
now  occupies  its  place.  The  cause  of  these  disturbances  is  not  at 
present  clearly  seen,  from  the  fact  that  the  effects  have  not  been 
traced  in  a  longitudinal  direction  over  a  considerable  extent  of 
country  as  they  usually  may  be  in  such  cases. 


REPORT  OF  STATE  GEOLOGIST. 

Thus  far  no  similar  evidences  of  disturbances  of  coal  -  measure 
strata  have  been  observed  in  Iowa,  although  the  older  rocks  in  the 
adjoining  States  are  often  found  disturbed. 

No  minerals  of  value  except  coal,  have  been  discovered  in  this 
county,  and  it  is  hardly  probable  that  any  such  will  be  found.  Small 
quantities  of  iron  ore  have  been  found  in  this,  as  well  as  in  many 
other  of  the  coal  counties.  It  is  usually  in  the  form  of  small,  irreg- 
ular, lenticular  masses,  called  clay  -  iron  stone,  or  in  still  mere  irreg- 
ular masses  of  per  -  oxide  of  iron,  usually  called  red  haematite.  The 
latter  is  an  excellent  ore  of  iron,  but  to  be  profitable  it  must  exist  in 
large  quantities  and  easy  of  access.  One  can  not  fail  to  see  that 
these  small  quantities  of  iron  ore,  however  excellent,  are  valueless 
when  he  learns  the  fact  that  iron  ore  is  now  being  shipped  from  the 
famous  Lake  Superior  mines  to  the  furnaces  in  north  -  eastern  Ohio 
and  north  -  western  Pennsylvania,  which  were  built  for  smelting  the 
ores  of  their  own  regions.  Upon  the  completion  of  our  north  and 
south  railroads  the  iron  region  of  Missouri  will  supply  us  much  more 
cheaply  than  we  could  produce  that  metal,  even  if  our  supply  of  ore 
were  many  times  greater  than  it  is.  In  the  fissures  of  the  clay- 
iron  nodules  found  in  the  dark  shale  just  north  of  Ottumwa,  small 
quantities  of  the  sulphuret  of  zinc  were  found.  This  discovery  is 
valuable,  however,  only  as  an  interesting  fact  in  mineralogy. 

Wapello  county  is  well  supplied  with  timber,  which  will  always 
keep  wood  at  a  reasonable  price  for  those  who  prefer  it  to  coal  as  a 
fuel.  It  is  well  watered  by  the  Des  Moines  river  and  its  numerous 
tributaries,  as  well  as  by  numerous  excellent  springs.  Good  wells 
are  easily  obtained  almost  anywhere.  It  is  superfluous  to  say  that 
the  soil  is  excellent,  for  no  poor  soil  exists  along  the  great  valley  of 
the  Des  Moines. 

VAN  BUREN  COUNTY. 

Van  Buren  was  one  among  the  first  counties  in  the  State  known 
to  contain  coal,  consequently  some  of  the  oldest  mines  in  the  State 
are  found  here.  It  was  quite  fully  reported  upon  by  Prof.  Worthen 
in  the  reports  of  the  former  geological  survey;  and  the  principal 
object  of  my  visit  there  was  only  to  obtain  some  more  definite  ideas 
in  relation  to  its  coal. 


REPORT  OF  STATE  GEOLOGIST. 

Commencing  in  the  north  -  western  part  of  the  county,  all  the 
mines  were  visited  in  succession  which  were  in  a  condition  to  enter. 
The  first  was  McHugh's  mine,  on  section  seventeen,  township  sev- 
enty, range  eleven,  a  little  below  the  town  of  Independent.  The 
bed  is  about  three  feet  thick,  but  is  not  now  much  worked. 

Two  and  a  half  miles  eastward  from  the  last  named  town,  on  sec- 
tion ten,  township  seventy,  range  eleven,  Mr.  Rodefer  has  a  good 
mine  in  operation,  the  coal  of  which  is  of  good  quality  and  the  bed 
four  feet  thick.  On  the  same  section,  and  about  half  a  mile  further 
up  the  small  creek  upon  which  the  Rodefer  mine  is  situated,  there  is 
another  exposure  of  a  four-foot  bed  of  coal,  the  identity  of  which 
with  that  of  Rodefer's  mine  seems  impossible,  as  it  is  evidently  many 
feet  above  it. 

Upon  a  branch  of  the  same  creek,  near  the  last-named  exposure, 
another  is  seen  about  one  foot  in  thickness,  which  seems  to  be  sepa- 
rate from  both  the  others,  probably  lying  between  them.  Should  this 
supposition  prove  correct,  there  are  three  separate  beds  of  coal  in 
this  county,  all  of  which  are  to  be  seen  upon  section  10,  township 
70,  range  11.  The  thin  bed  just  mentioned  is  overlaid  by  shales  of 
the  same  character  and  containing  the  same  species  of  fossil  fish 
remains  as  the  upper  bed  does  in  Wapello  and  Monroe  counties. 
Half  a  mile  south  of  Business  Corners,  Mr.  Alexander  Findley  is 
working  a  mine  in  a  three-and-a-half-foot  bed,  which  has  supplied  a 
large  district  around  for  many  years.  About  a  mile  from  the  latter 
mine,  on  lands  of  Hon.  Eliab  Doud,  at  Doud's  Station,  several  open- 
ings were  formerly  made,  and  a  considerable  quantity  of  coal  taken 
out.  They  are  now  abandoned,  although  much  good  coal  may  doubt- 
less yet  be  obtained  here. 

At  and  in  the  vicinity  of  Keosauqua  several  openings  have  been 
worked  for  a  long  time,  but  to  the  extent  only  of  supplying  the  local 
demand.  The  bed  ranges  from  two  to  three  feet  in  thickness.  These 
openings  are  all  upon  the  right  bank  of  the  river,  but  there  seems  to 
be  no  good  reason  why  the  same  bed  should  not  be  found  beneath 
the  higher  lands  of  the  great  bend  in  which  Keosauqua  is  situated, 
where  they  are  above  the  level  occupied  by  the  limestone. 

Coal  has  formerly  been   mined  at   several   points  along  Chequest 

creek,  but  operations  are  now  suspended  there. 
15 


H4-  REPORT  OF  STATE  GEOLOGIST. 

A  couple  of  miles  northward  from  Bentonsport,  Mr.  Carter  is 
working  a  three  -  foot  bed  of  coal,  and  several  other  openings  have 
also  been  made  in  that  township. 

At  Farmington  very  large  quantities  of  coal  were  formerly  mined 
for  shipment  on  the  Des  Moines  Valley  Railroad  to  the  Keokuk  and 
other  markets.  On  the  south  side  of  the  river  there  the  principal 
mines  are  owned  by  Messrs.  Dibble,  Wright  &  Tuttle,  and  no  doubt 
they  can  yet  be  made  to  furnish  large  quantities  of  coal  whenever 
the  demand  will  warrant  it. 

On  the  north  side  of  the  river,  a  mile  above  Farmington,  a  New 
York  Company  own  and  formerly  worked  extensive  mines,  having  a 
branch  track  from  the  railroad.  In  the  northeastern  corner  of  the 
county,  near  Hillsboro,  several  mines  have  been  worked  for  several 
years  to  supply  a  local  and  northward  market.  Mr.  Martin  has  a 
mine  on  section  fourteen,  township  seventy,  range  eight,  said  to  be 
seven  feet  thick,  but  learning  that  it  was  not  in  a  condition  to  enter, 
it  was  not  visited.  There  is  evidently  much  coal  in  Van  Buren 
county,  but  at  present  it  is  only  worked  to  supply  local  demand. 

Both  the  magnesian  and  calcareous  members  of  the  St.  Louis  lime- 
stone (sub  -  carboniferous)  are  freely  exposed  along  the  valleys  of  the 
Des  Moines  and  its  larger  tributaries.  This  is  particularly  the  case 
from  Independent  nearly  to  Bentonsport.  At  the  latter  place  the 
Keokuk  limestone  appears  beneath  the  St.  Louis  limestone,  the  latter 
there  appearing  near  the  tops  of  the  hills.  The  same  limestones  are 
also  seen  in  similar  positions  at  Bonaparte,  but  upon  reaching  Far- 
mington the  Keokuk  limestone  has  dipped  down  beneath  the  river 
again,  and  the  St.  Louis  limestone  is  seen  occupying  a  position  near 
the  water  level. 

It  is  always  found  that  when  these  sub  -  carboniferous  rocks  are 
elevated,  the  coal  -  measure  strata  which  rest  upon  them  are  also 
elevated  with  them.  This  proves  that  the  elevation  took  place  since 
the  coal  -  measure  strata  were  deposited,  and  since  these  have  often 
suffered  denudation,  it  is  believed  that  this  was  accomplished  by 
glacial  action,  and  consequently  the  elevation  of  the  strata  took  place 
before  the  glacial  epoch. 

In  this  county  the  limestones  also  show  considerable  evidence  not 
only  of  unevenness  of  surface  at  the  time  of  the  deposition  of  the 


REPORT  OF  STATE  GEOLOGIST. 

coal  -  measure  strata  but  also  of  some  disturbance  during  the  time  of 
its  own  deposition.  This  is  shown  by  the  brecciated  character  of 
the  rock  in  many  places,  and  also  by  the  evidences  of  the  fracture 
and  slipping  of  some  portions  past  the  other,  producing  something 
approaching  to  what  are  called  faults.  These  fractures  are  always 
local,  and  can  not  be  traced  to  any  considerable  distance,  as  faults 
usually  can.  During  the  deposition  of  the  rock  the  disturbance  was 
often  so  great  as  to  break  up  the  continuity  of  the  beds  and  mix 
masses  of  limestone  with  the  sandstone  of  the  same  formation,  as 
may  be  seen  above  Thatcher's  mill  near  Keosauqua. 

These  disturbances,  together  with  the  erosion  which  the  formation 
seems  to  have  suffered  before  the  deposition  of  the  coal  -  measures, 
left  the  general  surface  so  uneven  then  that  it  has  had  the  effect  of 
causing  a  want  of  uniformity  in  the  thickness  of  the  beds  of  coal  and 
also  of  their  associated  strata.  Thus  in  this  county,  even  where  the 
continuity  of  the  coal  -  beds  can  be  made  out,  they  are  found  to  be 
in  good  workable  condition  in  some  places,  and  so  thin  in  others  as 
to  be  worthless.  Thus  the  best  mines  of  this  county  may  be  expected 
to  occupy  limited  but  not  necessarily  entirely  isolated  basins. 

The  St.  Louis  limestone  presents  at  least  three  distinct  subdi- 
visions in  Van  Buren  county,  which  are  more  distinctly  seen  in 
Keosauqua  than  elsewhere.  The  first  presents  the  usual  charac- 
ters of  that  limestone ;  is  about  twenty  -  five  feet  thick,  and  imme- 
diately underlies  the  coal  -  measure  strata  there,  as  usual  in  other 
parts  of  the  coal  -  field.  The  second  is  a  sandstone  about  twenty 
feet  in  thickness,  and  is  seen  well  exposed  just  above  Thatcher's 
Mill,  where  it  underlies  the  first.  This  sandstone  is  sometimes 
soft  and  shaly,  but  near  the  residence  of  Hon.  J.  Thatcher  it  pre- 
sents quite  a  firm  texture,  and  has  the  general  appearance  of  the 
coal  -  measure  sandstone  before  mentioned,  but  is  lighter  colored. 
Most  of  it  will  doubtless  serve  a  good  purpose  for  ordinary  build- 
ings, and  being  quarried  with  much  less  labor  than  the  ordinary 
limestone,  it  will  probably  be  found  desirable  for  many  purposes. 
The  third  division  is  magnesian  limestone,  and  is  to  be  seen  at  the 
water's  edge  below  the  dam  at  Kinnersly's  Mill. 

On  Lick  creek,  near  Kilbourne  station,  on  the  D.  V.  Railroad, 
Messrs.  Knapp  and  Wright,  of  Keosauqua,  own  extensive  quarries 


REPORT  OF  STATE  GEOLOGIST. 

of  light  -  brown  stone,  which  belong  to  th  emagnesian  portion  of  the 
sub  -  carboniferous  limestone.  These  rocks  were  extensively  quarried 
many  years  ago  for  the  Des  Moines  River  Improvement.  Bridge 
abutments  built  then  of  these  stone  are  standing  now  entirely 
unchanged,  showing  that  the  material  is  excellent  for  such  pur- 
poses. 

The  layers  are  massive,  yet  they  are  easily  worked  and  may  be 
obtained  of  almost  any  desired  size.  They  are  of  two  distinct  varie- 
ties, although  both  possess  nearly  the  same  color ;  the  lower  layers 
being  properly  magnesian  limestone,  and  the  upper  layers  being 
more  properly  an  arenaceous  limestone  with  a  little  carbonate  of 
magnesia.  Both  derive  their  brown  color  from  iron.  Both  varie- 
ties will  make  good  building  material,  but  I  think  the  arenaceous 
variety  a  very  superior  stone  for  heavy  masonry. 

The  upper  limestone  also  furnishes  much  good  building  -  rock,  and 
also  excellent  lime.  Messrs.  Castor  &  Tuttle  have  a  lime  -  kiln  just 
opposite  Keosauqua,  and  upon  the  same  ground  a  coal  -  mine,  from 
which  they  obtain  the  fuel  for  burning  the  lime. 

On  the  farm  of  Mr.  A.  W.  Mangum,  two  and  a  half  miles  from 
Keosauqua,  a  good  bed  of  fire  -  clay  is  found,  from  which  the  prin- 
cipal supplies  are  obtained  for  the  pottery  of  Mr.  R.  M.  Dickson,  at 
Yernon.  Mr.  Dickson  employs  twenty  hands  and  uses  two  kilns, 
manufacturing  all  kinds  of  common  pottery,  and  also  drain  -  tiles. 

No  minerals  of  practical  value,  except  coal,  have  been  found  in 
Van  Buren  county,  nor  does  it  seem  probable  that  any  such  will  be 
found.  Samples  ot  good  iron  ore  —  red  haematite  —  were  obtained 
from  lands  of  Hon.  J.  Thatcher  and  Mr.  Trebblecock,  near  Keo- 
sauqua, but  there  is  no  prospect  that  it  will  be  found  in  sufficient 
quantities  for  profitable  manufacture.  Indeed,  the  Missouri  and  Lake 
Superior  iron  regions  seem  destined  to  supply  the  whole  West  with 
iron  ;  for  their  ores  are  now  carried  long  distances  to  be  smelted 
with  profit  in  furnaces  which  were  built  for  the  purpose  of  smelting 
ores  from  the  grounds  they  stand  upon. 

Some  citizens  of  Farmington  within  the  last  two  years  have  bored 
an  artesian  well  to  the  depth  of  seven  hundred  and  five  feet.  It  is 
now  discharging  water  very  freely,  although  the  boring  is  not  tubed. 
It  has  been  conducted  in  i  tube  to  a  hight  of  forty  feet  above  the 


REPORT  OF  STATE  GEOLOGIST. 

top  of  the  well,  still  discharging  freely.  Thus  far  no  use  has  been 
made  of  it.  The  temperature  of  the  water  is  much  above  that  of 
common  well  -  water,  and  appears  to  taste  slightly  of  sulphuretted 
hydrogen. 

Hon.  C.  G.  Dibble  kindly  forwarded  a  quantity  of  it  to  the  labo- 
ratory for  analysis,  but  the  vessel  containing  it  was  unfortunately 
broken  in  its  passage,  and  no  opportunity  has  since  presented  itself 
for  obtaining  more. 

Mr.  J.  J.  Kinersly,  in  digging  a  well  on  his  farm  a  mile  northward 
from  Keosauqua,  came  down  upon  coal -measure  shale  within  fifteen 
or  twenty  feet  of  the  surface.  Water,  presenting  no  unusual  color, 
catne  in  somewhat  freely,  having  a  very  acid  and  acrid  taste,  so  that 
he  abandoned  the  well  for  ordinary  purposes.  An  analysis  of  this 
water  shows  it  to  be  very  strongly  impregnated  with  proto  -  sulphate 
of  iron  —  common  copperas  —  with  some  free  sulphuric  acid.  The 
substances  contained  in  this  water  are  so  cheap  in  the  market  that 
they  may  in  this  case  be  considered  entirely  worthless.  The  deep  - 
red  liquid  seen  standing  in  puddles  about  the  mouths  of  coal-mines 
is  of  the  same  general  character  as  that  of  Mr.  Kinersly's  well, 
except  that  the  per  -  oxidation  of  the  iron  gives  it  the  dark  color. 

MARSHALL  COUNTY. 

The  reason  why  this  county  is  so  briefly  reported  upon,  or  rather 
why  it  is  not  reported  upon  at  all  at  the  present  time,  is  because  it  lies 
directly  in  the  path  which  it  was  necessary  to  travel  to  reach  that 
portion  of  the  State  which  it  was  proposed  to  examine  for  peat  The 
immediate  surface  of  the  greater  part  of  Marshal]  county  is  under- 
laid by  sub  -  carboniferous  rock,  beneat  hwhichno  coal  need  be  sought 
for  but  upon  which  the  coal  -  measure  sandstone  is  seen  to  rest  at 
some  points  in  the  vicinity  of  Linn  creek. 

This  sandstone  and  its  associated  shales  has  no  doubt  a  consider- 
able development  just  beneath  the  surface  drift  and  soil  of  the 
western  and  southwestern  part,  although  they  may  not  be  exposed 
to  view.  The  general  dip  of  all  the  strata  being  to  the  southward, 
these  coal  -  measure  strata  would  be  expected  to  increase  in  those 
directions,  while  the  sub  -  carboniferous  rocks  before  mentioned,  pass 


118  REPORT  OF  STATE  GEOLOGIST. 

beneath  them  and  are  seen  no  more.  In  defining  the  borders  of  a 
coal  -  field,  geologists  designate  a  line  upon  the  map  within  which 
those  rocks  are  found  exposed  that  are  known  to  be  associated  with, 
and  of  the  same  geological  nature  as  the  coal,  although  no  coal  may 
be  discovered  by  them,  or  even  if  none  actually  exists  there.  Thus 
we  know  that  the  border  of  the  Iowa  coal  -  field  so  determined  runs 
through  Marshall  county  in  a  southeasterly  and  northwesterly 
direction. 

Although  there  are  some  instances  of  a  considerable  development 
of  coal  within  a  short  distance  of  the  well  defined  -  border  of  the 
coal  field  as  above  described,  as  for  example  near  Eldora  in  Hardin 
county,  yet  such  favorable  exceptions  are  not  often  to  be  expected. 
While  it  is  not  at  all  impossible  that  coal  may  be  discovered  in  the 
western  and  southwestern  portions  of  the  county,  yet  in  view  of  the 
facts  just  mentioned,  justice  requires  that  I  should  not  encourage  a 
large  expenditure  of  money  or  labor  in  the  search  for  it. 

The  rocks  of  the  eastern  and  central  parts  of  the  county 
have  been  spoken  of  as  sub  -  carbaniferous.  There  are  several 
distinct  formations  which  constitute  the  rocks  of  sub  -  carboniferous 
period,  most  of  which  are  found  in  our  State.  These  are  first  — and 
lowest  in  the  series  —  these  rocks  and  their  geological  equivalents 
which  are  seen  at  the  base  of  the  exposures  at  Burlington,  and  called 
by  the  Illinois  geologists  the  "^Kinderhook  group  ; "  next  the 
u  Burlington  limestone  :"  next  the  "  Keokuk  limestone  ;  "  next  and 
highest  in  the  series  in  our  State,  the  "  St.  Louis  limestone.  "  It  is 
the  latter  that  the  coal  -  measure  rocks  of  Iowa  are  usually  found 
resting  upon ;  but  the  sub  -  carboniferous  rocks  of  this  county  are 
geologically  equivalent  to  the  upper  part  of  the  Kinderhook  group, 
and  perhaps  also  to  the  lower  part  of  the  Burlington  limestone. 

Consequently  the  coal  -  measure  sandstone  which  rests  upon  the 
limestone  in  this  county  is  in  geological  language  unconformable  to 
it,  because  the  upper  Burlington  limestone,  Keokuk,  and  St.  Louis 
limestones  are  all  wanting  from  their  places  between  the  two. 

The  county  is  well  supplied  with  stone  for  building  purposes  and 
for  lime,  from  the  limestone  before  mentioned,  and  the  coal  -  measure 
sandstone  is  also  used  for  rough  masonry  to  a  limited  extent.  The 
general  surface  is  of  a  pleasing  and  gently  undulating  outline,  and 


REPORT  OF  STATE  GEOLOGIST. 

delightful  landscape  views  are  numerous.  The  soil  is  everywhere 
fertile,  but  perhaps  more  especially  so  along  the  beautiful  valley  of 
the  Iowa  river,  which  runs  obliquely  through  the  county  in  the  same 
general  direction  as  the  borders  of  the  geological  formations  before 
mentioned.  The  whole  region  is  well  watered  by  springs  and 
streams  of  constant  and  remarkably  pure  water. 

Timber  enough  for  the  use  of  the  present  and  prospective  inhab- 
itants is  found  in  the  groves,  and  in  large  bodies  skirting  the  streams. 
Thus  there  is  no  real  element  of  prosperity  wanting  to  make  Mar- 
shall county  one  of  the  most  prosperous  in  the  State. 

FRANKLIN   COUNTY. 

Although  it  was  expected  from  the  first  that  this  county  would  be 
found  to  contain  peat,  yet  it  was  thought  best  not  to  devote  time 
enough  at  present  to  the  full  examination  of  it,  but  to  go  to  the 
more  northern  counties  and  return  to  this  if  time  should  permit. — 
From  some  knowledge  of  the  general  character 'of  the  surface,  and 
from  information  since  received,  it  is  believed  that  large  quantities 
of  peat  exist  in  the  north  -  western  and  south  -  western  parts  of  the 
county. 

The  first  peat  observed  in  the  county  was  in  the  northern  part  of 
township  ninety,  range  nineteen,  a  little  north  of  the  farms  of 
Messrs.^  Smith  and  Hedge.  It  is  found  in  a  grassy  slough,  is  from 
two  to  four  feet  deep,  and  probably  covers  two  or  three  acres.  The 
peat  here  is  not  of  the  best  quality,  but  will  make  a  desirable  fuel 
when  thoroughly  dried.  About  half  a  mile  north  of  this  locality,  in 
another  slough,  a  real  mossy  peat  bog  of  limited  extent  is  to  be  seen. 
It  occupies  about  an  acre,  and  is  somewhat  peculiar  in  its  accumula- 
tion, for  it  is  raised  in  a  slightly  mound  -  like  form  above  the  surface 
of  the  surrounding  parts  of  the  slough  in  which  it  is  located,  so  that 
it  can  all  be  easily  drained.  A  spring  evidently  comes  out  here 
which  affords  constant  moisture  for  the  growth  of  the  moss  that 
forms  the  peat.  This  is  a  good  clear  article  of  peat,  free  from 
earthy  matter,  and  is  known  to  be  more  than  seven  feet  deep  in  the 
center,  but  thins  out  toward  the  edges. 

A  small  marsh,  containing  two  or  three  acres,  was  seen  in  the 
southeastern  part  of  township  ninety  -  one,  range  twenty.  It  is 


120  REPORT  OF  STATE  GEOLOGIST. 

covered  with  grass,  but  the  usual  moss  is  seen  to  thickly  cover  over 
the  surface  at  the  roots  of  the  grass.  The  peat  reaches  about  three 
feet  in  depth,  and  will  make  a  very  fair  fuel. 

Another  marsh  was  found  on  section  twenty  -  five,  township  ninety- 
two,  range  twenty,  two  miles  east  of  Hampton,  the  county  -  seat  of 
Franklin  county.  It  is  estimated  to  contain  twenty  acres  of  peat 
which  will  average  two  and  a  half  feet  in  depth.  Although  these,  and 
other  marshes  of  this  county  will  doubtless  furnish  large  quantities 
of  valuable  fuel,  it  can  not  be  too  strongly  urged  upon  the  inhabitants 
to  plant  largely  of  our  forest  trees,  for  there  is  no  danger  that  any 
of  them  will  not  grow  to  be  excellent  timber,  nor  any  danger  that 
the  supply  will  ever  be  too  great. 

Aside  from  the  comparatively  insignificant  portion  of  the  surface 
occupied  by  the  marshes,  there  is  hardly  an  acre  in  the  whole  county 
which  will  not  produce  a  good  crop  of  all  kinds,  for  the  farm  ;  and  a 
crop  of  trees,  although  slower  in  bringing  a  return,  will  eventually  be 
found  to  be  as  profitable  and  certain  as  any  other.  Beside  the 
certainty  of  pecuniary  reward  for  the  labor  and  money  thus  expended, 
there  is  the  consideration  of  a  duty  which  those  owe,  who  are  able  to 
perform  it,  to  provide  this  indispensable  material  for  their  children's 
use,  and  also  for  their  own,  in  the  chilling  winters  of  their  old  age. 

Let  those  theorize  who  will,  concerning  the  origin  of  the  prairies, 
but  every  day's  observation  in  the  whole  State  from  south  to  north, 
and  from  east  to  west  convinces  me  that  there  is  nothing  more 
certain  than  the  growth  of  all  kinds  of  our  native  trees  upon  prairie 
soil,  and  their  rapid  encroachment  upon  the  prairies  without  further 
aid  from  man  than  keeping  out  the  annual  fires. 

Extended  observation  has  also  convinced  me  of  the  fact  that  there 
is  now  more  timber  growing  in  Iowa  than  there  was  twenty  -  five 
years  ago. 

The  immediate  surface  of  this  county  is  underlaid  in  the  southern 
parts  by  rocks  of  sub  -  carboniferous  age,  and  in  the  central  and  north- 
western parts,  by  rocks  of  Devonian  age,  consequently  the  whole 
county  is  beyond  the  limits  of  the  coal  -  field.  It  is  well  watered, 
and  the  streams  and  springs  are  beautifully  clear.  There  is  a 
sufficient  supply  of  stone  for  all  ordinary  purposes  of  building,  and 
the  manufacture  of  excellent  lime.  The  surface  is  nearly  all  beautiful 


REPORT  OF  STATE  GEOLOGIST.  121 

aud  fertile  rolling  prairie  ;  the  groves,  and  strips  of  timber  along  the 
streams  afford  sufficient  fuel  and  fencing  for  the  use  of  the  present 
inhabitants,  the  only  deficiency  being  the  want  of  a  full  supply  of  this 
material  to  meet  the  demands  of  the  prospective  population  of  a 
region  otherwise  so  inviting. 

PEAT. 

It  was  intended  that  extensive  examinations  of  the  northern  part 
of  the  State  should  be  made  in  the  search  for  peat  in  the  autumn  of 
1866,  and  in  September  of  that  year  a  brief  article  was  published 
by  me  in  several  of  the  newspapers  of  the  State,  calling  attention  to 
the  fact,  and  stating  at  the  same  time  the  reasons  which  induced  the 
belief  that  peat  would  be  found  there.  The  substance  of  that  article 
is  repeated  in  the  following,  because  there  are  so  many  of  our 
citizens  who  are  unacquainted  with  that  fuel.  It  may  be  that  the 
following  description  of  the  conditions  under  which  peat  is  found, 
will  not  fully  answer  for  all  the  deposits  that  may  be  discovered  in 
the  State,  for  these  descriptions  were  drawn  from  observations  made 
principally  in  the  counties  of  Franklin,  Wright,  Cerro  Gordo, 
Hancock,  Winnebago,  Worth  and  Kossuth. 

Peat  had  its  origin  in  the  partial  decomposition  of  vegetable 
matter  under  water,  or  in  a  condition  of  great  moisture  on,  or  near 
the  site  of  its  growth.  In  some  parts  of  the  world,  having  a  moist 
atmosphere,  it  is  iound  occupying  elevated  positions ;  but  in  our 
State  it  may  usually  be  looked  for  in  low  marshes,  most  of  which 
have  doubtless  once  been  ponds.  Wherever  a  pond  has  existed, 
rank  grasses,  rushes  and  other  plants,  have  grown  upon  its  borders, 
and  the  frosts  of  each  returning  November  laid  them  beneath  its 
surface,  their  comminuted  fragments  narrowing  the  area  and  lessen- 
ing the  depth  of  its  waters  until  the  surface  become  the  proper 
habita  of  a  peculiar  moss  wliich  continues  to  flourish  upon  the 
rapidly  -  decomposing  bodies  of  the  parent  stems  without  a  proper 
root,  and  which,  with  the  remains  of  the  grasses  and  other  plants 
that  grew  with  it,  has  filled  some  of  them  with  the  carbonaceous 
matter  thus  produced.  A  few  of  these  ponds  we  find  only  partially 
so  filled,  a  large  margin  of  peat  marsh  surrounding  the  open  water 
in  the  middle. 
16 


}22  REPORT  OF  STATE  GEOLOGIST. 

Again,  upon  the  gentle  slopes  of  some  valleys,  a  belt  of  springy 
land  often  exists,  where  the  water  constantly  oozes  oat  along  a 
considerable  distance,  and  is  not  gathered  into  a  definite  spring 
stream.  Under  such  conditions  the  necessary  constant  supply  of 
water  will  be  furnished  for  the  growth  of  the  rnoss  and  other  plants, 
the  remains  of  which  form  the  peat.  In  such  cases  the  accumulation 
of  peat  is  not  in  the  bottom  of  the  valley,  but  upon  its  slope, 
commencing  just  where  the  water  begins  to  issue.  But  in  a  country 
so  dry  as  ours,  we  can  seldom  expect  to  find  peat  where  there  have 
been  no  ponds,  and  consequently  it  is  not  to  be  expected  in  the  well- 
drained  regions  of  our  State  in  large  quantities. 

At  the  close  of  that  period  in  our  earth's  history  known  among 
geologists  as  the  glacial  epoch,  when  the  continents  which  now  exist 
had  already  assumed  their  present  dimensions  and  shapes,  that  por- 
tion of  the  surface  in  which  our  State  is  situated  was  much  more 
uniform  than  it  now  is.  Shallow  depressions  only  existed  then,  and 
these  gave  initial  direction  to  the  courses  of  the  streams  into  which 
the  surface  waters  were  gathered. 

The  rains,  floods  and  frosts  of  the  unnumbered  years  that  have 
passed  since  then,  together  with  the  steady  flow  of  the  streams,  have 
worn  their  channels  deeper  and  deeper,  causing  the  deepening  also 
of  their  tributaries  as  well  as  the  small  ravines  which  lead  into  them. 
Thus  wherever  the  streams  are  numerous,  and  their  valleys  deep,  the 
country  is  perfectly  drained ;  and  consequently  few  or  no  ponds  are 
found.  But  in  a  region  where  streams  have  their  rise  the  depressions 
will,  for  a  part  of  the  year  at  least,  be  filled  with  water,  because 
there  is  no  accumulation  of  water  beyond  to  send  a  current  across 
them  to  cut  a  channel  for  their  outlet.  In  the  northern  portion  of 
Iowa  the  streams  are  numerous,  and  the  region  consequently  well 
drained ;  but  many  of  those  streams  having  their  rise  in  the  northern 
part  of  the  State,  the  physical  conditions  exist  there  which  are  neces- 
sary to  the  formation  of  peat.  It  must  not  however  be  understood 
that  peat  does  not  exist  elsewhere,  for  it  is  well  known  that  many 
excellent  deposits  are  found,  even  as  far  south  as  the  center  of  the 
State  ;  yet  the  northern  portions  may  be  regarded  as  pre  -  eminently 
its  peat  regions. 

The  general  surface  occupied  by  the  counties  before  named  is  of  a 


REPORT  OF  STATE  GEOLOGIST.  123 

more  or  less  undulatory  character,  and  although  not  possessing  very 
strongly  marked  features,  its  prairies  seldom  present  that  well  defined 
ocean -like  horizon  which  one  frequently  observes  upon  the  prairies 
further  to  the  southward.  A  very  large  proportion  of  the  surface  is 
prairie ;  that  is,  it  is  covered  with  the  usual  prairie  grasses  and 
plants ;  and  being  largely  destitute  of  trees,  it  presents  to  the  eye  a 
great  many  slight,  irregular,  rounded  elevations  associated  with  cor- 
responding depressions.  Some  of  these  depressions  are  occupied  by 
ponds  and  lakes  because  they  do  not  communicate  with  each  other  so 
freely  as  the  depressions  do  in  well  -  drained  regions ;  and  a  part  of 
these  ponds  and  lakes  have  become  changed  into  peat  marshes.  Why 
they  have  not  all  become  so  changed  is  not  known,  but  there  are  a 
few  ponds  and  small  lakes  in  this  region  which  show  little  or  no  ten- 
dency to  the  formation  of  peat,  even  along  their  shallower  borders. 
A  range  of  these  peatless  lakelets,  comprising  a  quite  a  number, 
exists  along  the  "  divide  "  between  the  Iowa  and  Boone  rivers  in  the 
counties  of  Hancock  and  Wright. 

They  vary  from  half  a  mile  to  a  mile  and  a  half  across;  to  some 
of  which  the  settlers  have  applied  appropriate  names  and  some  have 
none.  Indian  names  are  sometimes  beautiful  and  perhaps  appropri- 
ate, if  we  new  their  real  signification,  but  Indian  names  are  not 
popular  among  those  who  have  so  lively  a  recollection  of  the 
atrocities  of  Inkpadutah  and  his  murderous,  band,  and  who  have 
lived  so  near  the  scenes  of  their  carnage.  It  is,  therefore,  thought 
not  inappropriate  to  apply  the  personal  names  of  Iowa's  fair  daught- 
ers to  these  beautiful  lakelets.  Thus  Lake  Cornelia  will  be  found  to 
lie  principally  in  section  sixteen,  township  ninety  -  two,  range 
twenty  four.  Lake  Flora  is  near  the  southeast  corner  of  township 
ninety -four,  range  twenty  -five,  and  Lake  Mary  is  within  a  quarter 
of  a  mile  to  the  eastward  of  it.  The  two  last  named,  have  been 
called  Twin  lakes,  but  this  is  an  appellation  given  in  a  number  of 
instances,  in  the  northern  part  of  the  State,  to  lakes  which  happen 
to  lie  near  each  other.  Lake  Gertrude  is  about  three  miles  west  of 
Belmond,  lying  principally  in  section  twenty  -  eight,  township  ninety- 
three,  range  twenty  -  four.  Close  to  the  border  of  the  latter  lake  is 
a  small  pond  which  lies  five  or  six  feet  below  its  level,  and  well 


124  REPORT  OF  STATE  GEOLOGIST. 

illustrates  the  relation  which  the  peat  marshes  are   sometimes  found 
holding  to  each  other. 

The  streams  of  this  region  have  not  those  well  -  defined  bottom 
lands  which  are  so  characteristic  of  the  majority  of  the  streams  of 
Iowa,  but  there  is  generally  a  gentle  and  almost  imperceptable 
descent  from  the  higher  lands  between  them,  so  that  one  can  not  say 
where  the  highland  begins  and  the  bottom  ends.  The  whole  surface, 
from  near  the  streams  to  the  low  dividing  ridges,  is  undulatory,  so 
that  the  appearance  of  the  descent  is  sometimes  obscured.  Thus 
the  peat  marshes  are  as  numerous  among  the  low  knobs  of  the 
"  divides  "  as  they  are  nearer  to  the  streams. 

As  before  said  the  common  prairie  grasses  and  plants  cover  the 
general  surface,  but  usually  as  soon  as  the  border  of  the  peat  marsh 
is  reached,  there  is  a  sudden  and  almost  entire  change  of  vegetation. 
The  peat  vegetation  may  be  said  to  consist  of  a  single  species  of  moss 
and  another  of  a  peculiar  grass.  While  other  plants  may,  and  do 
often  grow  upon,  and  enter  into  the  composition  of  peat ;  mineral 
impurities,  such  as  common  soil  and  sand,  which  form  the  natural 
habitat  of  those  plants,  may,  from  this  circumstance,  be  expected  to 
have  been  diffused  in  the  peat  through  the  agency  of  floods,  high 
winds,  etc.;  because  these  mineral  constituents  of  soil  seem  to  be 
indispensable  to  the  growth  of  these  plants,  while  they  do  not  seem  to 
be  necessary  to  the  growth  of  the  moss  and  wire  -  grass.  The  peat  of 
marshes  near  the  banks  of  streams  is  subject  to  such  impurities, 
while  that  of  those  marshes  which  are  so  situated  that  they  can 
receive  no  washings  from  the  surrounding  surface,  is  found  compara- 
tively pure.  Such  marshes  are  covered  almost  exclusively,  with  the 
two  species  of  vegetation  just  mentioned.  Thus  a  very  correct 
judgment  may  often  be  formed  of  the  character  of  a  marsh,  by 
seeing  its  vegetation,  without  going  upon  it.  It  has  been  noticed 
that  where  the  scouring  rush  grows  profusely  among  the  real  peat 
vegetation,  we  do  not  usually  find  the  peat  very  thick,  nor  very 
pure ;  yet  none  of  the  marshes  are  entirely  free  from  this  rush. 

As  we  stand  upon  the  higher  land  and  look  over  one  of  these 
marshes,  almost  the  only  vegetation  growing  upon  it  which  meets 
the  eye  is  the  peculiar  grass  before  referred  to,  known  among  the 
inhabitants  as  wire -grass. 


REPORT  OF  STATE  GEOLOGIST. 

No  specimen  of  this  grass  was  found  in  flower  or  seed,  but  it  is 
seen  that  it  increases  and  renews  its  growth  by  lateral  budding  near 
the  roots.  These  roots  form  a  somewhat  loose  but  very  tough  sod 
upon  the  surface.  The  leaves  are  long,  slender,  somewhat  rounded 
and  cellular.  Being  of  nearly  uniform  length  —  two  or  three  feet  — 
the  level  marsh,  stretching  sometimes  more  than  a  mile  away,  presents 
much  the  appearance  of  a  lake,  as  the  wind  blows  over  the  waving 
grass.  This  is  the  general  appearance  of  the  peat  marshes,  but 
there  are  some  marshes  presenting  this  general  appearance  which 
contain  little  or  no  peat,  although  its  formation  there  is  probably 
in  progress.  These  are  generally  small  and  consequently  shallow. 
Considering  the  undulatory  character  of  the  surface  before  men- 
tioned, it  would  be  expected  that  the  smaller  marshes  would  be 
shallow,  but  this  would  of  course  depend  in  a  great  degree  upon 
the  abruptness  of  the  undulations.  Again,  there  are  very  broad 
marshes  in  a  comparatively  flat  region,  the  peat  of  which,  for  obvious 
reasons,  is  quite  shallow. 

Those  marshes  which  lie  upon  the  more  undulating  surfaces  are 
frequently  arranged  in  series,  each  successively  occupying  a  little 
lower  level  than  the  other,  and  not  far  apart,  like  the  pond  before 
mentioned  near  Lake  Gertrude.  In  such  cases  the  marshes  may  be 
easily  drained  from  one  to  another,  and  finally  into  the  brooklets  to 
which  they  give  rise. 

Approaching  the  marsh,  we  find  in  most  cases,  as  soon  as  we  reach 
the  moist  ground  in  the  vicinity  of  its  border,  the  presence  of  grow- 
ing moss  among  the  ordinary  prairie  grass  and  plants.  The  moss 
increases  in  quantity  as  the  surface  becomes  more  moist,  and  upon 
reaching  the  peat  surface  we  usually  find  it  covered  with  a  thick, 
soft  carpet  of  moss  at  the  roots  of  the  wire  -  grass.  As  we  walk 
upon  the  surface,  if  the  peat  is  of  any  considerable  depth,  we  per- 
ceive it  quaking  beneath  us,  producing  the  feeling  of  danger  that 
we  may  slip  through  the  loose  but  tough  sod  into  the  soft  material 
below.  Cutting  through  this  sod  with  a  sharp  spade,  and  lifting  out 
a  piece  as  deep  as  the  spade -blade,  we  find  it  a  thickly  interwoven 
mass  of  moss  and  grass  roots  in  different  stages  of  decomposition, 
which  increases  with  the  depth,  so  that  the  lower  portion  of  it  may 
be  easily  pulled  to  pieces  with  the  fingers.  This,  and  all  between  it 


126  REPORT  OF  STATE  GEOLOGIST. 

and  the  earthy  muck  at  the  bottom,  is  peat,  yet  the  sod  itself,  when 
dry,  will  make  a  good  light  fuel. 

Peat,  in  various  parts  of  the  world,  differs  much  in  quality  —  from 
a  fibrous  mass,  almost  as  light  as  sponge,  to  a  smooth,  homogeneous 
substance,  almost  as  dense,  when  dried,  as  coal.  Our  Iowa  peat  par- 
takes of  the  fibrous  character,  but  is  not  of  the  lightest  varieties. 
It  varies  considerably  in  quality,  or  perhaps  more  properly  speak- 
ing, in  ripeness,  by  which  is  meant  the  more  or  less  complete 
destruction  of  the  vegetable  texture  in  which  it  had  its  origin  as 
a  top  sod,  and  which  has  been  left  beneath  to  perfect  its  peculiar 
decomposition,  by  the  accumulating  growth  above.  Thus  when  we 
bring  up  specimens  from  various  depths  we  find  that  the  deeper  ones 
will  usually  dry  into  a  more  compact  mass  than  the  others.  This  is 
consequently  a  better  fuel ;  not  that  it  will  burn  any  more  perfectly, 
but  being  more  compact  it  is  more  durable  and  capable  of  producing 
a  more  intense  heat.  Peat  in  the  marsh  holds  within  its  substance 
almost  an  incredible  amount  of  water,  and  where  it  is  of  considerable 
depth  it  quickly  absorbs  the  rain  which  falls  upon  it,  the  surface 
rising  and  falling  to  a  limited  degree  as  the  moisture  dries  out  by 
evaporation,  or  is  supplied  by  the  rains  ;  consequently  the  surfaces 
of  the  deeper  marshes  have  no  water  standing  upon  them  during  the 
greater  part  of  the  year,  even  when  communicating  with  the  open 
water  of  an  adjoining  pond. 

The  citizens  of  Iowa  are  so  universally  acquainted  with  the  numbers 
used  in  the  government  land  surveys  that  no  explanation  is  deemed 
necessary  to  a  list  of  localities  presented  in  that  form.  Indeed  it  is 
the  only  method  by  which  localities  in  such  a  region  could  be  defi- 
nitely indicated.  The  marshes  indicated  in  the  list  were  all  visited 
and  tested  by  myself  in  person,  but  for  the  numbers  indicating  them 
I  am  indebted  chiefly  to  the  principal  inhabitants,  who  are  well 
acquainted  with  the  land  surveys,  and  many  of  whom  accompanied  me 
in  the  examinations.  They  indicate  that  the  marsh  lies  wholly  or 
principally  upon  the  sections  whose  numbers  are  given,  and  are  doubt- 
less in  the  main  correct.  The  number  of  acres  given  in  the  table  was 
.estimated,  not  measured,  but  an  effort  was  always  made  to  be  quite 
within  the  limits  of  truth.  The  depth  mentioned,  is  the  greatest  depth 
ascertained.  Most  of  those  indicated  as  six  feet  are  doubtless  deeper, 
for  that  was  the  length  of  the  probe  handle  used,  and  when  a  greater 
depth  was  reached,  a  hole  was  dug  with  a  spade  in  which  to  work  the 
probe.  Towards  the  borders  of  the  marshes  the  depth  was  of  course 


REPORT  OF  STATE  GEOLOGIST. 


127 


always  less  than  that  indicated  in  the  list,  but  the  borders  having  less 
than  two  feet  of  peat  were  always  excluded  from  the  estimates. 


NAME  OF  COUNTY. 

Marsb. 

Section. 

Township 

| 

1 

CERRO  GORDO    - 
WORTH.  .. 

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2 

3 

4 

5 

6 
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9 

10 

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18 

14 
15 

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33 
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15 
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5 
5 
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1  28 
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10 
3 
1 

(    9 

1    4 
16 

36 
11 
4 
35 
(16 
121 
21 
1 
28 
16 

97 
97 
97 
97 
97 
97 
97 
96 

96 
97 
100 
100 
100 
100 
99 
99 
99 
99 
99 
99 
99 
99 
99 
100 
100 
100 
100 
98 
98 
97 
97 
98 
100 
100 
100 
100 
98 
98 
97 
97 
97 
95 
95 
95 
95 
96 
94 
94 
93 
90 
90 
90 
95 
97 
96| 

21 
21 
21 
22 
22 
22 
22, 
22 
20 
19 
20 
20 
20 
20 
20 
20 
20 
21 
21 
21 
2:; 
2:1, 
23 
22 
22 
22 
22 
22 
22 
22 
24 
24 
25 
2! 
24 
24 
2! 
2:, 
2-\ 
2.-, 
24 
23 
24 
24 
24 
24 
25 
24 
24 
24 
24 
24, 
231 
21) 
28 
20 

:::::::::.:::::::':::::::::::::: 

::::: 

i 

r.. 

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WINNER  AGO.    ... 

l  

20 

21 
22 
2:] 

24 

25 

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30 

31 

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f  .  . 

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.  



L 

{ 



ANCOCK  - 

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1  

f  '                '  :  34 

:::.::::.::.::.."...".::  

35 

30 
37 
88 

U'J 

WKIGHT.  ...  .  .  ..« 
KOSSUTH  



CD 

8 

0 

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£ 

j.  200 

6 

) 
j-  100 

1 

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6 

125 

6 

150 

6 

100 

7 

50 

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4 

[  250 

8 

50 

5 

150 

5 

40 

4 

}  75 

5 

20 

4 

40 

o 

40 

7 

j-  450 

0 

40 

7 

j-  100 

7 

300 

7 

j-  300 

7 

40 

7 

50 

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100 

7 

1 

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7 

J 
j-iooo 

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500 

7 

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4 

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4 

80 

4 

500 

5 

150 

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100 

9 

100  1  6 


150 
250 

50 

40 

200 

100 


128  REPORT  OF  STATE  GEOLOGIST. 

The  foregoing  list  of  marshes  is  intended  by  no  means  to  be  a 
complete  one  for  the  region  named,  the  principal  object  being  to  call 
public  attention  to  the  fact  of  the  existence  of  large  quantities  of 
valuable  fuel  which  have  thus  far  been  overlooked.  All  the  marshes 
known  to  exist  in  this  region  were  not  visited,  and  many  were  seen 
that  are  larger  than  some  of  those  here  enumerated.  Besides  these, 
small  marshes  containing  from  ten  to  thirty  acres  each,  with  from 
two  to  four  feet  of  peat,  are  very  numerous.  These  are  not  included 
at  all,  although  they  will  be  capable  of  supplying  the  persons  who 
own  them  with  all  necessary  fuel  within  their  own  means.  Other 
beds,  again,  it  will  be  seen,  are  so  large  that  they  will  supply 
material  for  the  most  extensive  machinery,  as  soon  as  the  demand 
will  warrant  it.  Residents  of  this  region  have  estimated,  and 
perhaps  correctly,  that  the  counties  of  Cerro  Gordo,  Hancock, 
Worth  and  Wmnebago,  contain  four  thousand  acres  each  of  good 
peat  lands.  Certain  it  is  that  the  supply  is  so  abundant,  and  so 
generally  distributed,  that  it  will  be  very  difficult  for  capitalists  to 
obtain  a  monopoly  of  it.  Kossuih  county  has  been  only  partially 
examined,  but  it  is  known  to  contain  some  very  fine  marshes,  and  it 
is  expected  that  its  northern  part  will  be  found  to  contain  many 
more. 

In  other  parts  of  the  world  we  learn  that  peat  is  found  having  a 
depth  of  thirty  or  forty  feet;  but  we  have  as  yet  no  reason  to  expect 
the  discovery  of  any  such  beds  in  Iowa.  In  the  region  under 
discussion,  the  character  of  the  surface,  as  before  described,  forbids 
it ;  the  inequalities  are  too  gentle  to  leave  depressions  of  that  depth 
which  might  become  filled  with  peat.  The  majority  of  the  marshes 
have  probably  less  than  six  feet  of  peat  at  their  greatest  depth ;  yet 
some  are  already  known  to  be  more  than  eight  feet  deep. 

So  little  is  known  by  those  who  live  in  the  West  concerning  the 
use  of  peat,  that  many  questions  which  naturally  arise,  can  not  at 
present  be  answered.  From  the  fact  that  much  is  said  about  the 
manufacture  of  peat,  and  that  many  machines  are  offered  in  the 
market,  those  who  find  themselves  the  owners  of  peat  marshes 
earnestly  ask  the  question :  "  Is  it  indispensable  that  peat  must 
pass  through  a  process  of  manufacture  before  it  can  be  burned?  If 
so,  it  is  necessary  that  a  capitalist  with  $5,000  or  $10,000  should 


REPORT  OF  STATE  GEOLOGIST. 

stand  between  us  and  a  supply  of  fuel  from  our  own  lands  ;  or  may 
we  not  prepare  a  good  article  within  our  limited  means  ?" 

These  are  important  questions  and  will  be  answered  as  clearly  as 
possible,  It  is  not  indispensable  that  peat  should  be  manufactured 
before  it  is  burned,  for  it  has  been  used  in  the  crude  state  for  hun- 
dreds of  years.  Drain  the  marsh  by  cutting  one  or  more  ditches 
clear  through  it,  communicating  with  the  outlet,  and  put  a  gate  at 
the  outlet  that  you  may  protect  it  from  the  annual  prairie  fires  by 
flooding  it.  When  well  drained,  strip  off  the  sod  with  a  very  sharp 
spade.  Then  with  the  same  spade,  or  better  still,  with  an  Irish 
slane,  cut  the  peat  into  convenient  blocks,  dry  them  on  the  ground, 
and  store  them  in  a  dry  place  for  use.  The  slane  is  an  instrument 
something  like  a  spade  with  the  blade,  which  is  of  thin  steel,  about 
sixteen  inches  long  and  ten  inches  wide,  bent  at  right  angles  like  a 
carpenter's  corner  -  chisel,  so  that  the  two  sides  will  cut  the  width 
and  thickness  of  the  peat  block  at  the  same  thrust. 

This  is  the  simplest  method  of  its  preparation,  but  the  same  peat 
which  thus  prepared  will  answer  in  a  satisfactory  manner  all  the 
purposes  of  ordinary  fuel,  can  be  rendered  a  very  superior  article, 
both  for  domestic  and  manufacturing  purposes,  by  a  condensing  pro- 
cess of  manufacture.  The  advantages  gained  by  manufacture  are 
the  reduction  of  bulk,  so  as  to  require  less  storage  room,  and  the  in- 
crease of  density  enables  us  to  produce  a  hotter  fire  within  a  small 
space. 

Machines  have  been  constructed  for  compressing  peat  into  blocks 
when  partially  dried,  and,  although  the  fuel  is  much  improved 
thereby,  it  has  been  found  that  the  compressed  blocks  quickly  disin- 
tegrate by  absorption  of  moisture  from  the  atmosphere,  and  by  hand- 
ling, so  as  to  render  it  inconvenient  and  troublesome.  It  is  now 
generally  conceded  that  a  condensing,  and  not  a  compressing  process, 
is  the  proper  one  to  be  adopted  in  the  manufacture  of  peat ;  and 
this  view  is  without  doubt  the  correct  one.  The  condensing  process 
consists  in  grinding  the  peat  while  wet,  in  a  properly  constructed 
mill,  into  a  smooth  pulp,  which  is  then  moulded  into  convenient 
blocks,  without  great  pressure,  and  dried  for  use.  While  these 
blocks  are  drying,  the  cellular  spaces  which  existed  between  the 

fibres  of  the  crude  peat,  being  broken  up  by  the  grinding  process, 
17 


130  REPORT  OF  STATE  GEOLOGIST. 

they  shrink  into  a  compact  mass,  quite  unlike  the  light,  crude  peat 
from  which  it  was  manufactured.  When  thoroughly  ground  and 
prepared  in  this  manner,  it  shrinks  by  the  natural  process  of  drying 
alone,  into  denser  masses  than  blocks  .of  the  same  peat  would  be 
when  dry,  after  having  been  compressed  by  the  most  powerful 
machinery,  without  previous  grinding,  when,  of  course,  the  violent 
compression  would  be  useless. 

No  data  have  been  obtained  by  which  to  estimate  the  difference  in 
value  between  the  well  -  manufactured  and  crude  peat,  but,  judging 
from  specimens  in  my  possession,  it  is  certainly  as  great  as  that  be- 
tween bass-wood  and  good  hickory. 

Well  -  dried  hickory  is  probably  the  best  fire  -  wood  in  use,  but, 
from  the  fact  that  it  will  float  upon  water,  while  pure,  dry,  well- 
manufactured  peat  will  sink  in  it,  it  is  evident  that  the  latter  con- 
tains the  greatest  amount  of  combustible  matter,  bulk  for  bulk. 

There  is  no  doubt  of  the  value  of  the  large  condensing  machines, 
such  as  Leavitt's  and  others,  for  those  who  wish  to  establish  a  busi- 
ness for  the  manufacture  and  sale  of  peat,  but  a  great  desideratum 
is  a  small  machine  which  will  come  within  the  means  of  every  family 
in  the  peat  regions,  so  that  they  may  prepare  their  own  fuel  by  their 
own  labor.  Peat  being  much  improved  in  quality,  even  by  an  im- 
perfect grinding,  it  is  not  improbable  that  small  machines  may  soon 
be  introduced  that  will  produce  an  excellent  article  of  domestic  fuel, 
in  a  more  convenient  form  than  it  usually  is  when  taken  from  the 
marsh  without  preparation. 

Upon  comparing  samples  of  Iowa  peat  with  my  specimens  from 
Ireland,  and  from  various  parts  of  our  own  country,  no  doubt  is 
entertained  that  ours  is  all  of  excellent  quality,  nor  that  it  will  soon 
become  invaluable  in  the  settlement  of  the  region  where  it  is  found. 
Estimates  have  been  made  as  to  the  value  of  peat  compared  with 
wood  and  coal.  According  to  some  of  these  estimates  a  ton  of  well 
dried,  compact  peat  is  equal  in  heating  power  to  a  cord  of  hickory 
wood,  but  as  far  as  the  greater  part  of  the  Iowa  peat  region  is 
concerned,  it  is  perhaps,  sufficient  to  say  that  the  results  have  not 
been  disparaging  to  peat,  but  such  estimates  are  not  at  all  necessary 
in  this  case,  for  the  real  peat  region  lies  wholly  beyond  the  limits  of 


REPORT  OF  STATE  GEOLOGIST. 

the  coal -field,  and  the  timber  although  enough  for  the  present  inhab- 
itants, can  not  supply  a  tithe  of^the  fuel  which  the  prospective 
population  of  a  region  so  fertile  and  inviting,  will  soon  demand. 
Peat  has  there  a  local  value  which  can  never  be  questioned. 

Peat  may  be  burned  in  ordinary  fire  -  places,  grates  and  stoves, 
but  appliances,  peculiarly  constructed  for  its  use,  will  doubtless  be 
found  in  the  market  as  soon  it  is  generally  known  that  there  is  a 
demand  for  them,  and  experience  as  to  the  best  methods  of  its  use 
will  be  gradually  acquired.  Messrs.  Mumford  &  Emsley  of  Mason 
City,  are  making  great  efforts  to  introduce  the  use  of  peat  among 
the  inhabitants  of  their  neighborhood  and  have  just  started  a  small 
mill  for  its  manufacture  at  that  place.  These  gentleman  have 
resolutely  overcome  many  difficulties,  and  the  supervisors  of  Cerro 
Gordo  county  have  very  commendably  encouraged  them  by  giving 
them  a  favorable  contract  for  furnishing  the  county  offices  with  fuel. 

The  amount  of  fuel  which  the  marshes  of  this  region  may  be 
made  to  produce  is  immense ;  and  yet  they  are  not  sufficiently 
numerous  to  be-a  reproach,  as  they  are  in  some  parts  of  Ireland ; 
nor  of  such  a  character  as  to  be  an  unsightly  blemish  upon  its  fair 
and  fruitful  surface. 

The  following  data  are  believed  to  be  reliable  as  to  the  amount  of 
peat  to  be  obtained  from  a  given  number  of  acres,  and  of  its  value 
as  fuel ; 

Two  hundred  and  fifty  tons  of  dry  fuel  per  acre  of  well  -  drained 
marsh  for  every  foot  in  depth ;  the  marsh  being  estimated  to  settle 
from  one  quarter  to  one  third  of  its  original  depth  by  draining. 

Thus  we  may  estimate  upon  the  annual  allowance  of  thirty  tons 
of  peat  to  each  family,  that  one  hundred  und  sixty  acres  of  peat, 
four  feet  deep  will  supply  two  hundred  and  thirteen  families  with 
fuel  upward  of  twenty -five  years. 

Knowing  the  rapidity  with  which  our  forest  trees  will  grow  upon 
our  soil,  this  would  give  ample  time  to  grow  a  supply  of  fuel  to  be 
used  when  the  peat  should  become  exhausted.  c 

Having  necessarily  been  familiar  with  the  few  diseases  prevalent 
in  Iowa,  I  took  particular  care  while  in  the  region  of  peat  marshes 
to  make  inquiries  and  observations  concerning  the  health  of  the 


132  REPORT  OF  STATE  GEOLOGIST. 

people  who  live  there.  The  time  occupied  by  my  examinations  was, 
that  portion  of  the  year,  when  malarial  diseases  prevail  (if  they 
ever  do)  ;  but  I  did  not  see  or  hear  of  a  single  case  of  those  diseases 
nor  of  any  other.  The  presence  of  the  peat  marshes  is  evidently  in 
no  way  prejudicial  to  health,  from  the  fact  that  the  profuse  vegeta- 
tion does  not  reach  a  complete  state  of  decomposition,  the  resulting 
peat  being  itself  antiseptic  in  its  properties. 

After  the  examinations  referred  to  in  the  foregoing  pages  were 
made,  three  important  marshes  in  the  central  parts  of  the  State  were 
visited,  beside  one  in  Whiteside  county,  Illinois.  It  has  been  ob- 
served in  the  northern  part  of  the  State  that  those  marshes  whose 
vegetation  is  almost  exclusively  wire  -  grass  and  moss  contained  the 
purest  peat,  and  that  those  which  contained  a  greater  proportion  of 
foreign  matter  had  a  mixed  vegetation  growing  upon  them.  These 
marshes  in  the  central  parts  of  the  State  all  have  a  somewhat  mixed 
vegetation,  yet  the  peat  is  usually  very  pure.  Whatever  may  be  the 
character  of  the  more  conspicuous  vegetation,  the  moss  is  always 
present  upon  all  marshes,  and  always  enters  largely  into  the  compo- 
sition of  the  peat. 

Peat  has  been  manufactured  from  all  but  one  of  these  during  the 
past  season,  and  from  these  sources  some  very  encouraging  data  were 
obtained  concerning  its  manufacture  and  the  great  favor  with  which 
it  is  received  as  a  fuel  by  those  who  have  tried  it. 

The  first  marsh  visited  is  situated  in  Muscatine  county,  principally 
upon  section  fifteen,  township  seventy -seven,  range  four,  eight  miles 
south  of  West  Liberty,  and  about  twelve  miles  from  Muscatine.  It 
contains  about  one  hundred  and  fifty  acres  of  peat,  and  the  depth  is 
reported  to  reach  thirteen  feet  in  some  places.  This  marsh  is  on  the 
line  of  the  Burlington  &  Cedar  Rapids  Railroad,  three  -  quarters  of 
a  mile  from  the  right  bank  of  Cedar  River,  and  occupies  an  ancient 
bed  of  that  river  which  was  deserted  as  it  cut  its  channel  deeper,  so 
as  to  leave  a  pond  there  which  is  now  beyond  its  highest  floods. 
This  pond,  supplied  with  a  large  part  of  the  necessary  moisture  by 
springs  which  ooze  out  from  the  base  of  a  sandy  bluif  about  twenty 
feet  high  which  partly  encircles  the  marsh,  has  become  filled  with 
peat. 


REPORT  OF  STATE  GEOLOGIST.  13 3 

The  reason  why  other  similar  depressions  left  by  the  receding  river 
have  not  become  so  filled,  may  perhaps  be  found  in  the  fact  that  they 
do  not  possess  the  surroundings  that  this  one  does,  namely  :  stretch- 
ing away  from  the  low  bluff  which  borders  the  marsh  is  a  level  tract 
of  land  which  is  itself  bordered  on  the  west  by  another  low  ridge 
having  the  general  direction  of  the  course  of  the  river.  Along  the 
base  of  this  ridge  is  marshy  ground,  but  it  is  not  a  peat  marsh, 
although  it  doubtless  occupies  a  still  more  ancient  bed  of  the  same 
river.  Between  these  two  marshes  the  soil  and  subsoil  is  sandy,  so 
that  the  water  which  falls  upon  the  level  tract  quickly  percolates 
through  to  the  peat  marsh  or  to  the  river.  The  peat  of  this  marsh 
is  good,  and  it  will  be  of  great  value  to  the  region  where  it  is  located. 

The  next  marsh  visited  contains  about  thirty  acres,  and  is  situated 
on  section  eleven,  township  eighty  -  three,  range  six,  about  four  miles 
west  of  Marion,  Linn  County.  It  is  reported  to  reach  ten  feet  in 
thickness,  but  where  it  is  now  worked,  it  is  about  five  feet  deep  of 
drained  peat.  Mr.  Hoffman  and  Mr.  Cougill  are  the  owners  of  the 
land,  but  Messrs.  Traer  and  Bundy  have  leased  it,  and  have  com- 
menced manufacturing  the  peat  for  market,  using  a  machine  which  is 
an  invention  of  the  last  -  named  gentleman.  It  was  not  in  operation 
at  the  time  of  my  visit,  but  some  very  good  specimens  of  the  peat 
prepared  by  it  were  obtained  for  the  State  collections.  This  is  one 
of  the  best  examples  of  a  "spring  marsh"  yet  seen.  It  lies  wholly 
upon  the  gentle  slope  bordering  one  of  the  upper  branches  of  a 
tributary  of  Cedar  River,  hardly  reaching  the  branch  itself.  It  is 
fed  with  moisture  by  springs  which  issue  along  this  slope,  while 
upon  the  opposite  one  there  is  little  or  no  peat,  doubtless  because 
few  or  no  springs  exist  there.  The  deposit  is  so  rounded  in  its 
central  portions  that  in  general  aspect  it  has  very  much  the  appear- 
ance of  one  of  the  ordinary  elevations  of  the  undulating  surface  of 
that  vicinity.  The  marsh  has  been  easily  drained  by  cutting  a  ditch 
from  its  upper  to  its  lower  border,  in  which  pure  water  flows,  a 
perpetual  spring.  The  above-named  firm  are  producing  a  good 
article  of  fuel,  and  will  no  doubt  be  able  to  supply*  the  demand  next 
year. 

Another  marsh,  containing  about  two  hundred  and  fifty  acres,  two 
hundred  acres  of  which  contains  peat  of  good  workable  depth,  is 


134  REPORT  OF  STATE  GEOLOGIST. 

found  in  Clinton  County,  upon  section  twenty  -  nine,  township 
eighty  -  one,  range  two,  about  two  and  a  half  miles  south  of  Calamus 
station  on  the  Northwestern  Railway.  A  dense  fog  prevailed 
during  the  whole  day  this  marsh  was  visited,  so  that  the  surrounding 
features  of  the  country  could  not  be  seen,  but  there  are  some  indi- 
cations that  it  was  formerly  a  pond.  The  subsoil  of  the  region 
around  it,  however,  being  sandy,  it  is  quite  probable  that  it  has 
derived  its  moisture  largely  from  springs. 

A  firm  have  established  machinery  here  for  the  manufacture  of 
peat,  but  the  season  closed  before  they  were  fairly  able  to  introduce 
the  fuel  to  the  market.  Mr.  Isaac  Heald,  of  West  Liberty,  one  of 
the  proprietors,  informs  me  that  they  expect  to  prosecute  the  busi- 
ness energetically  as  soon  as  the  spring  opens. 

In  Illinois,  about  seven  miles  eastward  from  Clinton,  there  is  a 
very  large  peat -marsh  where  two  or  three  machines  have  been  in 
effective  operation  during  the  past  season.  At  this  marsh  an  oppor- 
tunity was  had  to  see  some  very  satisfactory  results  of  the  manufac- 
ture, although  none  of  the  machines  were  in  operation.  The  blocks 
of  peat  manufactured  here  are  almost  as  dense  as  coal,  and  Mr. 
Dodge,  one  of  the  proprietors,  informs  me  that  he  has  not  been  able 
to  supply  the  demand  which  already  exists  for  it  at  seven  dollars  per 
ton.  He  also  tells  me  that  the  cost  of  manufacture  does  not  exceed 
two  dollars  per  ton.  Here  is  a  profit,  then,  which  ought  to  satisfy 
any  one. 

A  ton  of  prepared  peat  being  equal  in  value  to  a  cord  of  hickory 
wood,  and  the  latter  averaging  throughout  the  State,  after  being 
prepared  for  the  stove,  at  least  six  dollars  per  cord,  it  is  easy  to  see 
that  peat  will  be  valuable  anywhere.  But  this  is  not  the  only  way 
to  estimate  the  value  of  peat  to  the  northern  part  of  the  State. 
For  instance,  if  by  some  possible  disaster  all  the  forest  trees  of  a 
region  dependent  upon  that  source  alone  for  fuel,  should  be  swept 
out  of  existence.  The  loss  would  not  be  the  market  value  alone  of 
the  fuel  destroyed,  but  that  loss  would  greatly  lessen  the  value  of  all 
the  other  property  of  the  region  thus  affected.  The  converse  of  this 
is  also  true;  a  region  possessing  all  other  elements  of  wealth,  but 
heretofore  supposed  to  lack  one  essential  element,  receives  additional 


REPORT  OF  STATE  GEOLOGIST.  135 

value  by  the  discovery  of  that  element.  The  assurance  that  a  suffi- 
cient amount  of  fuel  exists  in  those  almost  treeless  but  fertile 
regions  of  Northern  Iowa,  will  cause  its  settlement  nearly  a  genera- 
tion before  it  otherwise  would  be. 

GYPSUM. 

Although  gypsum  has  been  known  to  exist  in  the  vicinity  of  Ft. 
Dodge,  in  Webster  county,  for  more  than  twenty  years,  the  public 
have  had  very  little  information  concerning  it.  Information  of  this 
kind  being  desirable  to  the  people  of  the  State,  about  two  weeks  of 
last  October  were  given  to  the  examination  of  the  region  by  myself 
and  Mr.  St.  John,1  upon  my  return  from  the  peat  region  further  north. 
Although  all  the  exposures  of  gypsum  are  found  within  an  area  of 
six  miles  in  extent,  northward  and  southward,  and  three  miles  east- 
ward and  westward,  the  amount  of  material  is  so  -great  that  it  is 
practically  inexhaustible,  and,  withal,  it  is  one  of  the  most  remarka- 
ble deposits  of  this  substance  yet  known. 

The  region  round  about  has  the  general  prairie  surface  so  charac- 
teristic of  a  large  portion  of  Iowa,  but  along  the  Des  Moines  River 
and  its  tributaries  there  is  a  good  supply  of  timber  covering  the 
valleys  and  slopes  which,  with  the  bold  features  of  the  river  valleys, 
give  many  interesting  landscape  views,  and  make  Ft.  Dodge  one  of 
the  most  pleasantly  located  towns  in  the  State.  The  river  has  eroded 
its  valley  here  to  a  depth  of  more  than  one  hundred  and  twenty  feet 
from  the  general  prairie  level,  and  it  is  along  its  steep  bluffs  and  upon 
the  sides  of  the  creek  valleys  and  ravines  which  lead  into  it  that  the 
gypsum  is  found.  It  is  exposed  in  bold  quarry  -  fronts,  having  in 
the  distance  almost  the  exact  appearance  of  limestone,  and  one  at 
first  finds  it  difficult  to  believe  that  it  is  any  thing  else.  At  one 
exposure  on  the  southwest  quarter  of  section  thirty  -  three,  township 
eighty  -  nine,  range  twenty  -  eight,  we  measured  twenty -eight  feet  in 
perpendicular  thickness  of  solid  gypsum.  There  is  no  do«ubt  that  it 
reaches  thirty  feet  in  thickness  at  that  place,  further  into  the  bluff, 
and  it  is  believed  to  be  equally  thick  in  other  places.  The  gypsum 
rests  upon  shale,  which,  when  exposed  to  atmospheric  influence, 
softens  into  clay.  Upon  this,  large  masses  have  slidden  down  in  some 


136  REPORT  OF  STATE  GEOLOGIST. 

places  from  their  natural  position,  increasing  the  apparent  thick- 
ness of  the  gypsum  deposit,  but  we  saw  nothing  to  convince  us  that 
it  is  anywhere  much  more  than  thirty  feet  thick.  The  lines  of  strati- 
fication are  horizontal  and  well  marked,  and  no  doubt  is  entertained 
that  the  formation  is  continuous  horizontally  over  a  great  portion  of 
the  area,  and  perhaps  further,  just  as  limestone  formations  are. 

Gypsum  in  other  parts  of  the  world  is  often  found  in  irregular 
masses  associated  with  shales  and  limestone,  but  here  the  deposit  is 
one  of  solid  gypsum,  not  intermixed  with  layers  of  shale  or  any 
other  substance.  It  is  proper  to  say,  however,  that  all  we  yet  know 
of  this,  or  other  deposits,  leads  to  the  belief  that  ours  may  not 
actually  extend  much  beyond  the  region  in  which  it  has  been  dis- 
covered. The  clearly  defined  base  of  the  gypsum  was  several  times 
found,  but  the  top  of  it  is  always  indefinite  in  consequence  of  erosion 
by  water  which  reaches  it  from  the  surface. 

The  base  of  the  gypsum  deposit  being  so  well  defined  we  were 
able  to  clearly  ascertain  that  it  rests  unconformably  upon  the  strata 
beneath  it.  In  consequence  of  this  unconformability  and  the  fact 
also  that  it  contains  no  fossils,  we  do  not  know  with  certainty  its 
geological  age  ;  but  it  is  probably  much  later  than  the  carboniferous 
age,  since  the  strata  of  that  age  are  now  well  understood  in  the  west, 
and  no  true  unconformability  has  been  found  to  occur  among  them  in 
Iowa,  above  the  sub  -  carboniferous.  Any  one  may  recognize  this 
unconformability  by  going  down  Two  -  mile  creek  from  the  exposure 
just  mentioned  where  the  base  of  the  gypsum  is  seen  resting  upon 
the  coal  -  measure  shales.  Following  down  the  creek  he  sees  the 
shales,  clays  and  sandstone,  as  well  as  a  little  coal,  exposed  at 
intervals  along  the  creek,  and  the  gypsum  above  it  all  in  the  sides  of 
the  hills.  Reaching  the  mouth  of  the  creek  and  going  three  -  quar- 
ters of  a  mile  down  the  river  shore  he  will  find  a  small  exposure  of 
the  same  limestone  formation  that  is  seen  in  Lizzard  and  Soldier 
creeks  above  town.  He  will  thus  have  passed  down  through  a 
vertical  thickness  amounting  to  about  one  hundred  feet.  Now  let 
him  go  to  Mr.  Mitchell's  gypsum  quarry  on  Soldier  creek,  which  is 
about  five  miles  to  the  northward  from  the  last  named  locality,  and 
he  will  find  the  base  of  it  in  such  position  that  it  must  rest  almost, 


»        REPORT  OF  STATE  GEOLOGIST.  137 

if  not  directly  upon  the  limestone  which  Mr.  Cummins  is  quarrying 
for  his  kilns  a  few  rods  distant ;  showing  that  although  some  coal 
measure  shales  ,are  exposed  on  Soldier  creek  they  are  wanting  at  this 
particular  point.  This  is  what  is  meant  by  unconformability,  and  it 
gives  in  this  case,  satisfactory  evidence  of  the  want  of  other  forma- 
tions between  the  coal  -  measures  and  the  gypsum.  The  limestone 
just  mentioned  is  known  by  its  fossils  to  be  the  same  as  that  on 
Lizzard  creek,  and  also  that  just  mentioned  on  section  five,  township 
eighty  -  eight,  range  twenty  -  eight.  It  is  sub-carboniferous  limestone, 
and  although  not  seen  in  all  places  along  the  river  and  creeks, 
doubtless  underlies  the  whole  region  at  no  great  depth. 

The  principal  exposures  of  gypsum  are  three  or  four  miles  below 
Fort  Dodge,  but  some  important  ones  are  almost  within  the  city 
limits.  Upon  sections  six  and  seven,  township  eighty  -  eight,  range 
twenty  -  eight ;  sections  one,  two  and  twelve,  township  eighty  -eight, 
range  twenty  -  nine,  and  section  thirty  -  three,  township  eighty  -  nine, 
range  twenty  -  eight,  they  are  very  extensive  and  easily  accessible. 
Very  important  exposures  are  also  found  on  other  sections,  all  of 
which  have  been  mapped  by  us  for  publication  in  the  final  report, 
and  we  estimate  that  following  down  all  the  creeks  and  ravines  in  the 
region,  limited  as  it  is,  one  will  find  not  less  than  seven  miles  of  con- 
tinuous exposure  of  gypsum,  upon  which  quarries  may  be  opened 
anywhere  by  a  day's  labor. 

Masses  of  a  few  hundred  pounds  weight  of  white  gypsum,  almost 
chemically  pure,  have  been  found  associated  with  that  of  the  main 
deposit,  but  so  far  as  observed  they  seemed  to  be  somewhat  concre- 
tionary in  form,  and  partially  detatched  from  it.  The  main  deposit 
is  of  a  rather  uniform  grey  color,  somewhat  in  shade  like  that  of  a 
printed  page,  yet  plaster  -  of-  paris  prepared  from  it  is  nearly  white. 
It  has  been  fully  tested  at  the  Geological  Rooms,  and  found  inferior 
to  none  in  quality. 

It  may  be  necessary  to  state  for  the  benefit  of  some  readers  that 
gypsum  is  a  chemical  compound  of  sulphuric  acid,  lime  and  water. 
It  is  much  softer  than  ordinary  stone,  and  when  crushed  and  ground 
to  a  fine  powder  in  an  ordinary  grist  -  mill,  it  goes  by  the  common 
name  of  "  plaster,"  in  which  form  it  is  largely  and  beneficially  used 
as  a  fertilizer.  If  this  dry  powder  is  placed  over  the  fire  in  an  iron 
18 


138  REPORT  OF  STATE  GEOLOGIST. 

cauldron  it  boils  as  if  water  had  been  artificially  added  to  it.  This 
is  caused  by  the  escape  of  the  water  before  mentioned,  which,  when 
thus  chemically  combined,  although  nothing  but  common  water,  is 
just  as  much  a  solid  as  the  lime  is  with  which  it  combines.  When 
the  boiling  has  ceased  the  powder  consists  of  sulphuric  acid  and 
lime  alone,  in  which  form  it  is  called  "  plaster  -  of  ~  paris, "  and  is 
used  in  the  arts  for  stucco  work,  models,  ornaments,  statuary,  &c. 

When  plaster  -  of -paris  has  been  long  kept  it  absorbs  water  from 
the  atmosphere,  and  thus  approaches  its  original  condition  again.  It 
can  be  fully  restored  to  its  former  quality  by  re -boiling,  of  course 
adding  no  water. 

The  reason  why  objects  formed  in  plaster  -  of-  paris  do  not  shrink 
in  the  process  of  drying,  as  other  substances  do  when  mixed  with 
water,  is  because  a  large  part  of  the  water  used  to  mix  the  powder 
with,  enters  again  into  chemical  union  with  it,  and  is  not  again  evap- 
orated at  ordinary  temperatures. 

The  principal  uses  to  which  gypsum  is  applied  are  those  just  men- 
tioned, but  the  people  of  Fort  Dodge  have  been  using  it  in  the  place 
of  common  stone.  Some  years  ago,  Hon.  John  F.  Duncombe  built 
a  large,  fine  residence  of  it  in  the  city,  and  he  informs  me  that  he 
is  perfectly  satisfied  with  it  as  a  building  material.  Several  other 
smaller  buildings  have  been  built  of  it,  and  large  slabs  which  some 
of  the  quarries  afford  make  excellent  sidewalks,  because  they  do  not 
become  slippery  as  stone  walks  do.  We  have  no  information  that 
gypsum  has  ever  been  used  as  a  building  stone  anywhere  else  than 
at  Fort  Dodge,  consequently  its  citizens  are  as  competent  to  decide 
that  question  as  any  one,  but  the  following  facts  are  worthy  of  con- 
sideration in  estimating  its  value  for  such  purposes.  About  three 
parts,  by  weight,  of  gypsum  are  soluble  in  one  thousand  parts,  by 
weight,  of  water.  If  water  which  already  holds  gypsum  in  solution, 
rests  upon  it,  it  will  not  be  affected  thereby,  but  if  it  be  exposed  to 
the  action  of  running  or  falling  water,  it  will  be  rapidly  destroyed. 
This  effect  is  often  seen  where  little  rills  of  water  caused  by  the 
rains,  run  over  the  face  of  an  unused  quarry,  and  cut  deep  grooves 
into  it,  sometimes  giving  it  the  appearance  of  melting  ice  around  a 
waterfall. 

When  built  into  the  walls  of  a  house  only  a  small  portion  of  its 


REPORT  OF  STATE  GEOLOGIST.  139 

surface  is  exposed  to  occasional  rains,  the  effect  of  which  must  be 
very  slow,  indeed,  upon  it.  This  effect  can  be  almost  entirely  pre- 
vented by  an  occasional  coat  of  linseed  oil,  which  also  improves  its 
beauty,  as  can  be  seen  in  Mr.  Duncombe's  house.  Wooden  buildings 
require  such  protection,  and  even  with  it  are  probably  no  more 
durable  than  those  built  of  gypsum,  for  those  J;hus  far  built  of  the 
latter  material  show  no  signs  of  failure  or  decay.  With  the  imme- 
diate prospect  that  Fort  Dodge  now  has  for  railroad  communication, 
her  gypsum  quarries  must  become  very  valuable. 

By  rough  estimate  it  is  calculated  that  there  is  now  annually  used 
in  our  State  about  seven  thousand  dollars  worth  of  plaster  -of-paris, 
for  mechanical  and  artistic  purposes  alone,  all  of  which  is  brought 
from  other  States,  and  from  the  province  of  Nova  Scotia ;  the  near- 
est of  which  localities  is  more  distant  from  our  State  than  Fort 
Dod^e  is  from  the  most  remote  town  within  it.  Should  themanufac- 

o 

ture  of  plaster  be  commenced  at  Fort  Dodge,  the  State  of  Iowa 
would  not  furnish  the  only  market  for  it,  but  Minnesota,  Nebraska, 
and  parts  of  Missouri,  Illinois  and  Wisconsin  would  also  find  it  more 
convenient  to  obtain  their  supplies  of  this  material  from  Fort  Dodge 
than  from  any  other  source. 

This  estimate  does  not  include  fertilizing  plaster,  which  it  is 
believed  will  largely  benefit  even  the  rich  soils  of  Iowa,  for  it  is 
doubtful  whether  the  action  of  plaster  upon  soil  is  so  much  a  fer- 
tilizer, in  the  common  meaning  of  the  term,  as  an  agent  effecting  the 
retention  of  moisture.  In  either  case,  its  effects  are  beneficial. 

Allowing  that  the  gypsum  does  not  extend  beneath  the  greater 
part  of  the  area  before  mentioned,  as  it  is  believed  to  do,  but  that 
it  is  no  more  than  fifty  feet  wide  from  the  face  of  the  exposures, 
and  only  twenty  instead  of  thirty  feet  deep,  the  following  figures 
show  the  supply  of  material  that  can  be  obtained  from  the  estimated 
seven  miles  of  exposure  ;  36,960,000  cubic  feet  of  material  as  quarry 
rock,  or  2,648,800  tons  of  plaster  for  fertilizing  purposes,  or 
2,092,860  tons  of  plaster-  of  -  paris  for  use  in  the  arts.  These  esti- 
mates are  based  upon  the  following  data  :  Quarry  gypsum  weighs 
143  J  pounds  per  cubic  foot.  When  this  is  separated  from  its  water 
of  crystalization  by  heat,  it  leaves  113J  pounds  of  plaster  -  of  -  paris. 
These  estimates  are  believed  to  embrace  only  a  fraction  of  the 


140  REPORT  OF  STATE  GEOLOGIST. 

amount  of  material  which   actually  exists  there,  and  are  only  given 
to  call  attention  to  the  great  importance  of  that  deposit. 

Gypsum  is  much  more  easily  quarried  than  stone.  Instead  of 
being  drilled  for  blasting,  it  is  bored  with  an  augur  as  readily  as 
wood,  and  blocks  are  dressed  into  any  desired  shape  with  common 
axes  and  saws,  instead  of  being  done  with  stone-masons'  tools. 
Thus  the  labor  of  preparing  it  for  building  purposes  is  much  less 
than  that  required  for  the  preparation  of  stone  for  the  same  uses. 

Salt  is  so  often  found  in  connection  with  gypsum  deposits,  that 
the  suggestion  often  arises  whether  we  may  not  expect  to  find  it  in 
connection  with  that  deposit  at  Ft.  Dodge.  All  that  can  be  said 
upon  this  point  is  that  no  indication  of  the  presence  of  salt  in  that 
region  has  yet  been  observed,  and  that  since  we  are  quite  well 
acquainted  with  the  condition  and  character  of  the  strata  which 
underlie  the  gypsum,  the  probabilities  that  a  salt  deposit  exists 
there  are  not  encouraging. 

COAL,  STONE,  &c.,  AT  FT.  DODGE. 

The  season  being  so  near  its  close,  very  little  time  could  be  given 
to  the  examination  of  the  coal  -  measure  strata  in  this  vicinity  ;  but 
enough  was  seen  to  convince  us  that  the  Ft.  Dodge  region,  as  a  coal- 
producing  district,  has  been  much  underrated.  There  is  good  reason 
to  believe  that  the  coal  -  field  does  not  extend  much  to  the  northward 
of  the  city,  but  there -is  evidence  that  up  to  a  point  four  or  five  miles 
below  the  city  there  is  a  very  important  development  of  the  produc- 
tive coal  -  measures. 

A  short  time  was  spent  in  that  vicinity,  in  company  with  Mr.  Dun- 
combe,  visiting  the  mines  and  exposures  of  coal.  These  are  princi- 
pally along  Holladay's  creek,  and  the  branches  which  lead  into  it, 
and  also  into  the  river. 

We  saw  evidence  of  the  existence  of  four  different  beds  of  coal 
here,  all  lying  above  the  level  of  the  Des  Moines  River,  two  of  which 
are  very  important.  One  of  these  beds  is  known  to  reach  a  thickness 
at  one  point  of  nearly  five  feet.  This  is  now  thought  to  be  the  highest 
bed  in  the  series  in  this  vicinity,  but  we  are  not  fully  satisfied  upon 
this  point.  It  is  believed  to  be  one  of  the  lower  beds  that  is  operated 
by  Hon.  Samuel  Rees,  near  the  bank  of  the  river,  just  below  town. 


REPORT  OF  STATE  GEOLOGIST. 


141 


This  is  evidently  not  very  far  above  the  limestone,  and  is  probably 
the  lowest  bed  of  bituminous  coal  in  the  region.  Thomas  Sargent, 
Esq.,  has  an  exposure  of  coal  at  his  farm  on  Lizzard  creek,  some 
four  miles  west  of  town,  which  is  believed  to  be  identical  with  the 
bed  of  Mr.  Rees'  mine,  and  if  so  there  is  probably  no  other  coal 
beneath  it,  unless  it  be  the  bed  of  impure  cannel  coal  which  is  seen 
in  the  river  bank,  on  section  seventeen,  township  eighty  -  eight, 
range  twenty  -  eight,  which  bed  also  probably  underlies  Mr.  Rees' 
mine. 

The  sub  -  carboniferous  limestone,  before  mentioned  as  occurring  at 
the  base  of  the  coal  -  measures  at  Ft.  Dodge,  is  known  by  its  fossils 
and  general  characters  also  to  belong  to  the  St.  Louis  division,  and 
is  identical  with  that  so  often  mentioned  before  as  forming  the  floor 
(so  to  speak)  of  the  coal-measures  in  Marion,  Mahaska,  Wapello, 
Yan  Buren,  Jefferson  and  other  counties  to  the  southward,  as  well  as 
in  Hamilton,  the  next  county  eastward  from  Webster.  This  lime- 
stone seems  to  rise  and  disappear  with  considerable  rapidity  to  the 
northward,  after  its  appearance  from  beneath  the  river  in  the  vicinity 
of  Ft.  Dodge.  Mr.  Cummins  manufactures  large  quantities  of  excel- 
lent lime  from  it  on  Soldier  creek,  just  north  of  town,  and  both  upon 
this  and  Lizzard  creek  much  building  stone  may  be  obtained.  Along 
the  Des  Moines  river  for  a  distance  of  a  few  miles  there  are  also 
large  exposures  which  thus  far  have  remained  almost  untouched,  be- 
cause the  gypsum  is  obtained  with  less  labor  for  the  same  uses  that 
common  stone  is  usually  applied  to. 

In  some  places  in  the  vicinity  considerable  quantities  of  the  ordi- 
nary coal -measure  sandstone  are  to  be  obtained,  some  of  which 
would  make  good  coarse  building  material,  but  much  of  it  is  poor. 

In  the  spring  of  1866,  a  very  small  deposit,  containing  a  few  hun- 
dred pounds  of  fine  columnar  sulphate  of  strontia  was  found  in  the 
coal  -  measure  strata  near  Mr.  Rees's  mine  just  below  town,  and  at 
the  top  of  the  gypsum  on  Soldier  creek,  a  small  quantity  of  the  same 
mineral  was  also  found.  This  is  believed  to  be  the  first  instance  of 
the  discovery  of  that  mineral  in  Iowa.  It  is  true  it  has  very  little 
economic  value,  except  that  it  is  used  to  produce  the  red  light  in 
fire  -  works,  but  it  is  very  interesting  to  the  mineralogist. 


'142  REPORT  OF  STATE  GEOLOGIST. 

BOONSBORO  COAL  MINES. 

While  on  the  way  home  at  the  close  of  the  season  a  very  brief 
visit  was  made  to  the  coal  mines  at  Boonsboro. 

These  mines  are  opened  at  intervals  along  each  side  of  the  valley 
of  Honey  creek,  which  empties  into  the  Des  Moines  river  near 
Boonsboro  and  also  along  the  hill  sides  bordering  the  river ;  all  of 
them  opening  almost  directly  upon  the  Northwestern  Railway.  Two 
beds  are  now  being  worked  here,  one  of  which  is  a  little  over  three 
feet,  and  the  other  two  feet  in  thickness.  These  it  will  be  seen, 
although  they  furnish  large  quantities  of  good  coal  are  not  by  any 
means  so  heavy  beds  as  some*  others  in  Iowa ;  and  yet  there  are  no 
mines  in  the  State  which  have  a  greater  present,  and  perhaps  I 'may 
add,  a  greater  prospective  value,  than  those  of  Boonsboro.  This 
arises  from  their  unusually  favorable  location,  affording  them  a  good 
market  at  high  prices,  and  also,  from  the  further  fact  that  they  are 
intelligently  and  extensively  worked.  A  number  of  the  mines  are 
in  the  hands  of  private  individuals,  but  far  the  greater  part  of  the 
coal  land  is  held,  and  the  coal  taken  out  by  two  companies,  the 
Northwestern  Coal  Company  and  the  Moingona  Coal  Company. 
The  former  company,  beside  the  products  of  its  own  extensive 
mining,  purchase  a  great  part  of  the  coal  taken  out  by  private 
parties  for  shipment  with  their  own.  Much  the  greater  part  of 
the  coal  which  this  company  ships,  goes  to  the  great  Pacific  Rail- 
way, the  Northwestern  Railway  being  supplied  principally  by  the 
Moingona  Company.  From  the  fact  that  these  two  great  lines  of 
railway  consume  nearly  all  the  coal  of  this  region  as  fast  as  it  is 
mined,  very  little  has  hitherto  been  known,  by  the  general  public,  of 
the  importance  of  the  Boonsboro  mines. 

The  Northwestern  Coal  Company  are  shipping  about  one  hundred 
tons  of  coal  per  day,  and  this  is  probably  not  much  more  than  half 
of  the  aggregate  amount  mined  per  day  in  that  neighborhood.  All 
the  coal  is  sold  as  fast  as  it  is  raised,  and  the  demand  is  constantly 
increasing.  The  energy  with  which  these  mines  are  worked  gives 
some  faint  indication  of  the  immense  quantities  of  coal  which  our 
mines  in  other  parts  of  the  State  will  furnish  when  railroad  facilities 
and  other  improvements  shall  have  opened  a  market  for  it. 


MISCELLANEOUS. 


OBSERVATIONS    UPON    THE    DRIFT  PHENOMENA  OF  SOUTH- 
WESTERN IOWA. 

The  following  article  was  first  published  in  the  American  Journal 
of  Science  and  Arts  (Silliman's  Journal),  for  May,  1867 : 

In  the  year  1858,  I  discovered  distinct  glacial  scratches  upon  an 
exposed  layer  of  the  Upper  Burlington  limestone  (sub-carboniferous), 
and  made  full  notes  and  drawings  of  the  same,  which  having  been 
unfortunately  destroyed  by  fire  within  a  year  afterward,  no  account 
of  the  observations  was  ever  published.  No  opportunity  has  since 
presented  itself  to  verify  those  observations,  but  I  think  I  am  not 
mistaken  in  the  recollection  that  there  was  but  one  set  of  scratches, 
which  were  straight,  distinct,  and  rather  numerous ;  having  a  direction 
south,  about  twenty- two  degrees  east.  This,  so  far  as  I  am  aware, 
was  the  first  observation  of  glacial  scratches  upon  rocks  in  situ  in 
the  State  of  Iowa,  although  boulders  with  similar  scratches  upon 
them  are  often  seen  in  various  parts  of  the  State. 

During  my  official  labors  last  season,  although  considerable  atten- 
tion was  given  to  the  drift  deposit,  no  similar  traces  of  glacial  phe- 
nomena were  ever  discovered,,  until  I  reached  the  Missouri  River  in 
Mills  county,  where,  on  section  sixteen,  township  seventy-one,  range 
forty-three,  west  of  the  fifth  principal  meridian,  very  distinct  glacial 
scratches  were  found  upon  limestone  of  the  upper  coal  -  measures  not 
far  from  the  middle  of  the  series. 

The  locality  is  upon  the  western  abrupt  slope  of  the  bluffs  which 
border  the  bottom  land  of  the  Missouri  River.  The  river  being  dis- 
tant nearly  three  miles  to  the  westward,  the  exact  hight  of  the 
scratches  above  it  was  not  definitely  ascertained,  but  it  is  probably 
not  much  less  than  one  hundred  feet  above  the  ordinary  stage  of 
water.  About  four  feet  in  thickness  of  ordinary  drift  material  rested 


144  REPORT  OF  STATE  GEOLOGIST. 

upon  the  straited  surface.  This  had  been  partially  removed  by  the 
quarrymen,  exposing  the  scratches  to  view.  Resting  upon  this  light 
deposit  of  drift,  and  sloping  upward  to  the  high  lands,  are  about  one 
hundred  and  fifty  feet  of  that  peculiar  lacustrine  deposit  called  by 
Dr.  Owen  "  siliceous  marl,"  and  by  Prof.  Swallow  the  "  bluff  forma- 
tion," which  deeply  covers  the  drift  and  underlying  rocks  of  this 
region,  except  where  they  have  been  exposed  by  fluviatile  denuda- 
tion. 

The  boulders  and  pebbles  contained  in  the  drift  material  of  this 
locality  are  both  granitic  and  metamorphic.  They  are  well- 
rounded  and  worn,  and  straited  faces  were  observed  upon  quite  a 
number  of  them,  thus  as  nearly  as  possible  detecting  them  in  the 
very  act  of  scoring  the  rocks  in  situ. 

The  scratches  here  are  in  two  sets,  a  coarser  and  a  finer ;  those  of 
the  latter  more  numerous  than  the  former,  but  those  of  both  sets 
being  perfectly  parallel  with  their  fellows,  distinct  and  straight.  The 
surface  of  the  rock  had  been  ground  level  and  smooth,  removing  all 
unevenness  of  the  natural  bedding  surface.  The  directions  of  the 
striae  were  determined  by  a  very  good  pocket  -  compass.  That  of  the 
coarser  set  (No.  1)  was  found  to  be  S.  20°  E.,  and  that  of  the  finer 
set  (No.  2)  S.  51°  E.  No  allowance  was  made  in  either  case  for  the 
variation  of  the  magnetic  needle,  which  the  local  surveyers  calculate 
at  about  eleven  degrees  east  of  north. 

At  an  exposure  of  the  same  limestone  one  mile  below  Omaha>  the 
capital  of  Nebraska,  immediately  upon  the  right  bank  of  the  Missouri 
river,  and  only  some  six  or  eight  feet  above  the  ordinary  stage  of 
water,  other  scratches  of  a  similar  character  were  observed.  They 
were  found  upon  the  upper  surface  of  a  firm  layer,  which  the  work- 
men had  exposed  and  were  removing  for  building  purposes.  Here, 
however,  there  is  but  one  set  of  scratches,  their  direction  being 
S.  41°  W.  (set  No.  3),  not  allowing  for  variation  of  the  magnetic 
needle.  The  surface  of  the  rock  is  nearly  or  quite  level,  but  the 
roughness  of  the  natural  bedding  surface  has  not  been  entirely 
removed,  yet  the  strise  were  so  distinct  that  no  difficulty  was  found 
in  ascertaining  their  true  direction. 

The  drift  at  this  locality  is  principally  composed  of  a  dark  colored, 
stiff,  clayey  material,  intermixed  with  sand,  gravel  and  boulders,  and 


REPORT  OF  STATE  GEOLOGIST.  14  5 

varies  from  one  foot  to  eight  feet  in  thickness.  Upon  this  rests  the 
bluff  formation  as  before  described.  The  face  of  the  bluff  at  the 
locality  where  the  latter  observations  were  made  is  nearly  at  right 
angles  with  the  direction  of  the  striae. 

Considering  that  the  whole  region  surrounding  these  localities,  and 
for  a  long  distance  to  the  northward  of  them,  is  an  entirely  open 
country ;  that  the  present  prominently  uneven  features  of  the  region 
had  their  origin  at  a  period  subsequent  to  the  drift ;  and  the  extreme 
simplicity  and  uniformity  of  the  strata  over  which  the  glaciers  must 
have  moved,  the  direction  of  their  currents  which  these  scratches 
apparently  indicate  seems  very  remarkable.  We  not  only  see  at  the 
Mills  county  locality  that  the  scratches  upon  one  and  the  same 
surface  prove  that  two  separate  currents  existed  there  during  some 
portions  of  the  glacial  epoch,  having  a  divergence  of  thirty  -  one 
degrees  with  each  other,  but  also,  only  about  twenty  miles  to  the 
northward,  we  find  the  evidence  that  another  current  moved  in  a 
direction  which  formed  an  angle  of  ninety  -  three  degrees  with  one  of 
those  in  Mills  county. 

Since  we  see  no  evidence  of  the  cotemporaneous  existence  of 
obstructions  which  might  have  deflected  the  current  of  a  regular 
southerly  -  moving  glacier,  and  thus  have  produced  the  scratches  in 
the  various  directions  shown,  it  seems  necessary  that  we  should  seek 
for  some  other  explanation  of  them.  Observations  thus  far  made 
certainly  afford  very  inadequate  data  upon  which  to  base  a  definite 
theory  concerning  the  real  direction  of  glacial  currents  over  this  part 
of  the  continent,  but  the  coincidence  of  the  direction  of  those 
scratches  which  have  been  observed  with  the  general  course  of  the 
drainage  of  the  region  in  which  they  occur,  is  worthy  of  careful 
consideration.  By  reference  to  the  mention  of  the  locality,  near 
Burlington,  at  the  commencement  of  this  article,  and  to  a  map  of 
Iowa,  it  will  be  seen  that  the  direction  of  the  scratches  observed  there, 
coincides  pretty  nearly  with  the  general  direction  of  the  drainage  of 
the  eastern  watershed  of  the  State. 

Set  No.  3  represents  a  current  coinciding  quite  as  nearly  with  the 
general  direction  of    the    drainage  upon    the   western   watershed; 
and  sets  No.  1  and  No.  2  respectively  represent  currents  approxim- 
ately coinciding  with  the  general  courses  of  the  Missouri  and  Platte 
19 


146  REPORT  OF  STATE  GEOLOGIST. 

Rivers.  That  the  close  of  the  drift  epoch  left  the  surface  of  our 
State  unmarked  by  strong  features,  and  with  shallow,  longitudinal 
depressions  which  gave  initial  direction  to  the  courses  of  the 
streams,  and  that  these  subsequently  cut  out  their  own  valleys  by 
erosion,  there  seems  to  be  no  reason  to  doubt.  It  seems  not  improb- 
able, also,  that  these  initial  depressions  in  the  surface,  whether 
primarily  caused  by  flexures  of  the  earth's  crust,  as  Whitney  has 
suggested,  or  not,  may  be  regarded  to  some  extent  as  indices  of  the 
general  direction  of  ancient  glacial  currents. 

There  is  another  interesting  matter  in  connection  with  these 
observations  of  drift  phenomena  along  the  Missouri  River,  and  the 
existence  of  the  important  lacustrine  deposit  there.  The  close  of 
the  drift  epoch  evidently  left  a  large  depression  of  the  general 
surface  in  the  region,  a  portion  of  which  is  now  occupied  in  part  by 
the  counties  of  Fremont,  Mills,  Pottawattamie,  Harrison  and 
Monona.  This  depression  became  a  large  fresh -water  lake,  the 
borders  of  which  have  not  yet  been  definitely  ascertained,  but  no 
satisfactory  evidence  of  its  existence  eastward  of  the  East  Nishna- 
botany  River  has  been  observed  in  Iowa.  The  Missouri  River 
evidently  emptied  into  this  lake,  and  flowed  from  it,  until  it  became 
filled  with  the  peculiar  deposit  of  fine,  siliceous,  marly  material, 
known  as  the  bluff  formation,  the  character  of  which  is  very  much 
the  same  as  that  of  the  muddy  material  which  would  now  bo  depos- 
ited from  the  waters  of  the  river  if  it  were  possible  to  throw  a 
permanent  obstruction  across  it.  As  the  valley  of  the  river  was 
gradually  deepened  during  the  Terrace  epoch,  its  waters  found  no 
difficulty  in  sweeping  out  the  fine  homogeneous  material  which  they 
had  before  deposited,  leaving  those  high  peculiar  bluffs  upon  each 
side  of  its  broad  bottom.  Fresh  -  water  and  land  shells  of  existing 
species,  principally  Gasteropods,  are  often  found  in  this  deposit, 
from  base  to  top,  and  its  thickness  sometimes  reaches  more  than  two 
hundred  feet  above  the  drift  material  upon  which  it  rests. 

Seventy  or  eighty  miles  to  the  eastward  of  the  Missouri  River,  in 
the  southern  tier  of  counties,  there  are  evidences  that  the  drift 
deposit  reaches  a  thickness  of  more  than  a  hundred  and  fifty  feet. 
Westward  from  that  region  a  sensible  diminution  of  its  thickness  is 
seen,  and,  reaching  the  region  of  the  bluff  formation  along  the 


REPORT  OF  STATE  GEOLOGIST.  147 

Missouri  river,   the  drift  material  is  found  in  all  cases  comparatively 
thin,  being  thinnest  where  the  bluff  material  is  thickest. 

At  the  localities  where  the  scratches  were  observed,  the  drift 
material  showed  evidences  of  unusual  violence  of  glacial  action, 
being,  as  before  remarked,  only  a  few  feet  in  thickness  ;  and  in  some 
places  in  the  same  neighborhood  it  was  entirely  wanting,  the  bluff 
material  resting  directly  upon  the  coal  -  measure  limestone. 

An  explanation  of  these  facts  is  naturally  sought  for.  The  most 
plausible  seems  to  be,  that  glacial  action  extended  more  deeply 
beneath  the  general  surface  here  than  elsewhere,  and  that  the  direc- 
tion and  character  of  the  currents  were  such  that  the  greater  part  of 
the  drift  material  was  swept  away  to  other  places,  leaving  the  lake 
basin  to  be  filled  with  water  at  the  close  of  the  glacial  epoch.  Fur- 
ther investigations,  however,  are  needed  to  decide  such  questions  as 
these. 

It  is  understood  that  the  most  reliable  information  we  can  obtain 
in  relation  to  the  general  direction  of  ancient  glacial  currents  will  be 
the  identification  of  the  transported  materials  with  those  at  the 
places  of  their  origin.  Very  few  observations  of  this  kind 
have  yet  been  attempted  in  Iowa,  and  it  is  but  fair  to  state  that 
those  few  are  not  now  seen  to  harmonize  clearly  with  the  directions 
of  the  glacial  scratches  just  described.  I  refer  to  the  reputed  dis- 
coveries of  galena  and  native  copper  in  several  of  the  counties  upon 
the  eastern  watershed  of  the  State.  The  only  known  localities  from 
which  such  materials  might  have  been  derived  lie  to  the  northeast- 
ward, in  a  direction  nearly  at  right  angles  with  the  eastern  drainage 
lines.  Again,  profusely  scattered  over  the  region  between  the  Mis- 
souri river  and  the  middle  of  the  State,  so  far  northward  as  the 
fourth  tier  of  counties  and  probably  much  farther,  are  boulders  and 
fragments  of  reddish  -  colored  quartzite,  closely  answering  the 
description  given  by  Dr.  Hayden  of  the  rock  which  encloses  the 
pipestone  of  southwestern  Minnesota,  and  suspected  to  be  of  the 
same  origin.*  Should  this  be  the  case,  it  is  not  easy  to  see  how 
they  could  have  reached  their  present  locations  with  glacial  currents 
in  the  direction  of  the  drainage  of  the  western  watershed,  particu- 


*  bee  F.  V.  Hayden  on  the  Geology  of  Northeastern  Dakota;  this   Journal, 
January,  1867. 


148  REPORT  OF  STATE  GEOLOGIST. 

larly  if  they  are  of  the  age  to  which  Dr.  Hayden  has  referred  the 
rocks  of  that  famous  locality  ;  for  in  that  case  they  can  not  be  pre- 
sumed to  have  ever  existed  much  farther  to  the  eastward. 

The  quartzite  boulders  in  the  region  referred  to  are  promiscously 
intermixed  with  those  of  other  metamorphic  and  of  granite  origin, 
but  those  of  the  red  quartzite  are  everywhere  a  little  less  waterworn 
and  more  angular  than  the  others,  suggesting  a  less  distance  of 
transportation,  which  would  really  be  the  case  if  derived  from  the 
pipestone  region. 

INDIAN  MOUNDS*. 

The  whole  history  of  the  American  continent,  previous  to  its 
discovery  by  Columbus,  is  so  wrapped  in  impenetrable  mystery,  that 
the  least  memento  of  its  ancient  inhabitants  is  regarded  with  unusual 
interest.  Of  the  race  which  existed  when  Europeans  first  visited 
America,  and  which  now  occupies  a  large  portion  of  it,  we  have 
comparatively  full  information ;  yet  of  their  origin  or  advent  upon 
the  continent,  we  know  nothing  with  certainty. 

Notwithstanding  this  want  of  knowledge  of  their  early  history,  the 
evidence  seems  to  be  satisfactory,  that  an  aboriginal  race  more 
ancient  than  they,  and  having  entirely  different  customs,  once 
inhabited  the  country  now  occupied  by  the  northern  and  north- 
western States,  as  well  as  parts  of  Canada. 

The  principal  features  of  this,  evidence  within  the  area  named, 
consists  in  the  remains  of  ancient  copper- mining  in  the  Lake 
Superior  region,  and  the  presence  of  what  are  commonly  known  as 
Indian  Mounds.  It  is  believed  that  the  present  race  of  Indians,  at 
the  time  of  the  first  visit  of  the  whites,  knew  nothing  of  the  working 
of  any  metal,  not  even  of  lead,  and  they  also  seem  to  be  in  as  utter 
ignorance  as  ourselves  concerning  the  origin  of  the  mounds. 

Thse  mounds  are  rounded  elevations  of  earth  evidently  scraped 
up  from  the  surrounding  surface ;  usually  small,  often  scarcely 
distinguishable,  but  occasionally  of  considerable  size.  They  are 
usually  circular,  sometimes  oval,  and  even  in  some  cases  bear  a 
fancied  resemblance  in  outline  to  some  animal.  They  are  almost 

*  From  the  Annals  of  Iowa  for  January,  1868. 


REPORT  OF  STATE  GEOLOGIST. 

invariably  in  groups,  numbering  from  two  or  three,  to  fifty  or  more. 
Sometimes  they  seem  to  be  arranged  on  a  definite  ground  -  plan,  but 
are  often  distributed  without  order. 

Concerning  the  purposes  for  which  they  were  constructed  we  are 
much  in  doubt,  but  they  are  usually  regarded  as  memorials  of  the 
dead.  Human  remains  have  often  been  found  in  connection  with 
them,  but  this  is  by  no  means  invariable.  When  such  remains  are 
found  they  are  usually  placed  around  the  base  of  the  mound,  where 
they  are  sometimes  marked  by  the  presence  of  flat  stones,  but  they 
seldom  if  ever  occupy  the  centre,  with  the  earth  heaped  upon  them. 
Rude  pottery  and  other  relics  are  frequently  found  with  these 
remains,  to  which  the  present  race  of  Indians  seem  to  be  entire 
strangers. 

The  mounds  commonly  occupy  prominent,  or  otherwise  interesting 
locations,  in  the  majority  of  cases  being  found  upon  the  brow  of  the 
bold  characteristic  bluffs  which  border  the  valleys  of  our  Western 
rivers,  but  are  not  unfrequextly  located  upon  an  elevated  plateau 
which  is  skirted  around  by  a  low  range  of  bluffs  or  hills.  Standing 
among  any  of  these  mounds,  one  finds  the  surrounding  scenery 
invariably  interesting,  and  often  very  impressive,  showing  that  a 
certain  sentiment  guided  the  builders  in  their  selection  of  the  ground, 
but  what  this  sentiment  was,  whether  of  religion,  veneration  of  the 
dead,  or  an  appreciation  of  the  beautiful  and  sublime  in  nature,  we 
are  left  to  conjecture.  They  are  quite  numerous  along  the  bluffs  of 
the  Mississippi  river,  and  the  lover  of  that  romantic  scenery,  having 
sought  out  some  point  from  which  to  obtain  a  view  more  beautiful 
and  impressive  than  the  rest,  will  almost  always  find  himself  in  the 
immediate  presence  of  a  group  of  mounds. 

During  the  progress  of  the  State  Geological  Survey,  many  of 
these  interesting  objects  have  been  observed,  but  the  press  of  other 
matters  has  prevented  that  careful  examination  of  them  which  the 
interest  of  the  subject  requires.  Along  the  bluffs  of  the  Iowa 
River  between  Iowa  City  and  Columbus  City,  a  large  number  of 
them  have  been  observed,  a  very  numerous  group  of  which  occur 
just  below  the  mouth  of  English  River,  about  twelve  miles  from 
Iowa  City.  An  interesting  group  is  found  on  the  land  of  Hon. 
Eliab  Doud,  near  the  Des  Moines  River  in  Van  Buren  County. 


150  REPORT  OF  STATE  GEOLOGIST. 

Visiting  Sac  City,  Sac  County,  last  autumn,  I  observed  several 
mounds  within  the  village,  and  having  no  time  to  devote  to  a  careful 
examination  of  these,  Mr.  D.  Carr  Early,  an  attorney  of  that  place 
has  kindly  furnished  me  with  data  for  the  following  account  of  them, 
accompanied  by  a  carefully  drawn  plat,  which  I  regret  can  not  be 
published  with  this  article. 

Sac  City  is  pleasantly  located  in  an  abrupt  bend  of  Raccoon  river, 
which  sweeps  around  it  upon  the  north,  east  and  south,  and  rests 
upon  one  of  those  level,  or  gently  inclined  spaces  called  by  the 
settlers  "  second  bottom."  They  were  doubtless  true  bottom  lands 
ages  ago,  long  before  the  river  had  cut  its  valley  so  deep  as  it  now 
is,  and  long  before  the  mound  -  builders  occupied  the  ground,  but 
they  are  now,  and  were  when  the  mounds  were  built,  some  of  the 
most  interesting  and  fertile  spots,  and  far  above  the  reach  of  floods. 
On  the  west  the  town  is  bordered  by  a  moderately  elevated  bluff,  and 
thus  the  whole  space  is  surrounded  by  strongly-marked  topograph- 
ical features  rendering  it  one  of  the  most  interesting  spots  in  the 
whole  region.  It  is  about  the  centre  of  this  space  that  we  find  the 
mounds,  and  doubtless  an  appreciation  of  the  surrounding  features 
guided  the  mound-builders  in  the  one  case,  and  the  town-builders  in 
the  other,  in  the  selection  of  grounds.  The  mounds  are  eight  in 
number,  arranged  in  a  general  direction  from  northeast  to  southwest, 
but  without  regular  order,  the  distance  between  the  two  extremes  in 
that  direction  being  a  little  less  than  six  hundred  feet,  and  in  the 
transverse  direction,  less  than  one  hundred  feet. 

Two  of  these  mounds  are  oval  in  outline,  and  all  the  others  are 
circular.  The  oval  ones  are  located  further  to  the  northeast,  and 
commencing  with  the  first  of  these,  which  is  near  his  residence,  Mr. 
Early  gives  their  dimensions,  as  follows,  progressing  in  the  order  of 
their  occurrence  to  the  southwest. 

No.  1,  96  feet  in  diameter,  east  and  west,  and  86  feet  north  and 
south,  and  two  feet  high. 

No.  2,  60  feet  in  diameter,  east  and  west,  and  30  feet  north  and 
south,  and  two  feet  high. 

No.  3,  circular,  66  feet  in  diameter  and  5  feet  high. 

No.  4,       "         80         "  "          "     6         " 

No.  5,       "         60         "  "          "     3         « 


REPORT  OF  STATE  GEOLOGIST. 

No.  6,  circular,  60  feet  in  diameter  and  3  feet  high. 

No.  7,      "        50        "  "          "     21      " 

No.  8,       "        60        "  "          "     3        « 

It  will  be  observed  that  .three  of  these  mounds  are  of  exactly  the 
same  dimensions,  and  that  the  long  axes  of  two  oval  ones  are  in  an 
east  and  west  direction,  and  not  in  the  line  of  their  distribution. 

Nos.  four,  five  and  six  have  been  dug  through  the  centre  to  the 
undisturbed  earth,  the  public  well  having  been  dug  through  number 
five,  and  the  flag  -  staff  set  in  number  six  ;  and  nothing  of  human 
remains  or  works  of  art  have  been  discovered. 

It  is  to  be  hoped  that  during  the  progress  of  the  State  work 
sufficient  time  may  be  devoted  to  the  careful  examination  of  these 
works  of  the  former  owners  of  our  soil. 

LAKES  OF  IOWA  —  PAST  AND  PRESENT. 

After  returning  from  the  northern  peat  regions,  I  published  in 
several  of  the  Iowa  newspapers  an  article  upon  "  Walled  Lakes." 
Subsequently  the  following  article  was  communicated  to  the  American 
Naturalist,  (Salem,  Mass.,)  and  is  inserted  here,  in  place  of  the  other, 
because  it  contains  some  additional  matter,  and  because  it  is  fuller 
upon  the  subject  of  those  lakes : 

Within  the  last  ten  or  fifteen  years  a  number  of  articles  have  ap- 
peared in  the  newspapers  and  periodicals  of  the  country  in  relation, 
more  particularly,  to  two  small  lakes  of  Northern  Iowa.  Some  of 
the  writers  have  contented  themselves  with  merely  a  description  of 
what  they  saw,  while  others  have  told  strange  stories  in  which  they 
described  the  "  remains  of  the  wonderful  handiwork  of  a  departed 
race  of  men."  While  in  that  part  of  the  State  during  the  past 
season,  excellent  opportunities  were  had  of  examining  both  of  the 
lakes  just  named,  as  well  as  others  of  the  same  character,  fourteen 
in  number,  of  which  the  following  is  a  list : 

1.  Clear  Lake,  Cerro  Gordo  county. 

2.  Rice  Lake,  Worth  county. 

3.  Silver  Lake,  Worth  county. 

4.  Bright's  Lake,  Worth  county. 

5.  Crystal  Lake,  Hancock  county. 

6.  Eagle  Lake,  Hancock  county. 


REPORT  OF  STATE  GEOLOGIST. 

7.  Lake  Edward,  Hancock  county. 

8.  Lake  Mary,  Hancock  county. 

9.  Lake  Flora,  Hancock  county. 

10.  Owl  Lake,  Humboldt  county. 

11.  Lake  Gertrude,  Wright  county. 

12.  Lake  Cornelia,  Wright  county. 

13.  Elm  Lake,  Wright  county. 

14.  Wall  Lake,  Wright  county. 

15.  Twin  Lakes,  Calhoun  county. 

16.  "  Wall  Lake,"  Sac  county. 

According  to  those  stories  the  remains  consisted  of  walls  of  huge 
stones  encircling  the  lakes  like  that  of  an  artificial  fish-pond,  so  raised 
as  to  prevent  an  overflow  of  water  upon  the  adjacent  low  ground, 
sloping  to  the  water's  edge  with  a  pavement  like  a  Mississippi  levee, 
rounded  and  graded  with  earth  upon  the  top,  forming  a  good  road 
upon  which  the  Jehus  of  that  departed  race  doubtless  drove  their  elk 
or  buffalo  chariots  in  pursuit  of  pleasure  or  of  their  daily  vocations, 
and  the  whole  finished  with  a  garniture  of  sage  reflections  upon  the 
mutability  of  human  affairs.  Such  fantastic  stories  have  rendered 
those  modest  little  lakelets  so  famous  that  many  pilgrimages  have 
been  made  to  their  borders  with  the  hope  of  finding  something  to  aid 
in  penetrating  the  mystery  that  shrouds  the  early  human  history  of 
our  continent. 

It  is  such  lakelets  as  these,  and  their  origin,  that  will  now,  in  part, 
engage  our  attention ;  and  while  showing  the  groundlessness  of  the 
stories  referred  to,  we  hope  to  present  still  more  interesting  and 
wonderful  facts,  because,  in  the  realm  of  nature,  truth  is  stranger 
than  fiction. 

First,  let  us  go  back  to  their  origin,  for  they  originated  from  causes 
so  definite  that  we  are  often  able  to  comprehend  them  as  clearly  as 
if  we  saw  them  in  operation  ;  and  the  time  of  their  formation  in  rela- 
tion to  other  geological  changes  is  as  accurately  determined  as  that 
of  any  other.  Not  only  have  the  lakes  had  a  definite  origin,  but,  as 
we  shall  presently  see,  some  of  them  have  also  had  an  end,  and  we 
know  they  once  existed  only  by  means  of  the  records  they  have  left 
in  the  earth  they  once  covered.  Hence  the  addendum  to  the  above 
title  —  past  and  present. 


REPORT  OF  STATE  GEOLOGIST.  153 

Lakes  have  doubtless  existed  upon  the  earth's  surface  in  every 
geological  age,  but  those  of  which  we  are  speaking  had  their  origin 
at  a  period  really  very  remote,  when  considered  in  relation  to  the 
historic  era,  but  very  recent  when  compared  with  the  geological  ages 
which  preceded  it. 

All  geologists  arc  agreed  that  at  the  close  of  the  Tertiary  age, 
after  the  stratified  rocks  had  been  formed,  and  before  the  present 
condition  of  things  existed  upon  the  face  of  the  earth,  a  long  period 
of  time  elapsed,  during  which  the  whole  northern  hemisphere,  as  far 
south  at  least  as  the  thirty  -  ninth  degree  of  north  latitude,  was  cov- 
ered thickly  and  constantly  with  ice ;  which  time  they  call  the  Glacial 
epoch.  All  are  not  entirely  agreed  as  to  what  condition  the  ice  was 
in,  whether  floating  in  a  shallow  sea  in  the  form  of  floes  and  ice- 
bergs, or  in  the  more  completely  frozen  condition  of  a  widespread, 
continuous  and  southerly  moving  glacier ;  yet  the  latterhy  pothesis 
is  generally  accepted  as  according  with  the  greatest  number  and  most 
important  of  known  facts.  All  are,  however,  agreed  that  the  boul- 
ders and  pebbles  which  we  see  every  where  scattered  over  the  face 
of  the  country  are  of  northern  origin,  and  that  they  have  received 
their  rounded  forms  by  attrition  in  water  or  moving  ice  during  the 
time  of  their  journeyings  from  their  northern  homes.  We  see  those 
boulders  and  the  gravel  upon  the  surface  only,  because  we  can  look 
no  deeper,  but  we  have  abandant  proof  that  they  are  intermixed  with 
all  that  incoherent  mass  of  material  which  geologists  call  drift  — 
that  material  which  meets  our  eyes  every  where,  forms  our  soil  and 
subsoil,  and  covers  all  the  stratified  rocks  like  a  mantle,  except 
where  they  have  been  bared  by  erosion.  Some  of  the  finer  material 
of  the  drift  was  doubtless  brought  from  the  north  with  the  boulders, 
but,  with  the  exception  of  the  latter,  it  has  been  largely  derived  by 
attrition  from  the  rocks  over  which  the  glaciers  passed,  or  from  those 
which  now  underlie  the  drift.  Thus  the  soil  is  nothing  more  than 
pulverized  rock,  and  the  whole  drift  formation,  composed  as  it  is  of 
boulders,  gravel,  sand,  clay  and  soil,  had  its  origin  as  such  through 
the  agency  of  ice. 

At  the  close  of  the  glacial  epoch  the  ice  disappeared  from  the 
temperate  zone,  the  present  condition  of  the  seasons  was  estab- 
lished, and  the  continent  assumed  very  nearly  its  present  dimensions 
20 


1 54  REPORT  OF  STATE  GEOLOGIST. 

and  form.  The  northern  part  of  the  Great  Valley  —  it  is  to  this 
region  which  more  especial  reference  is  made  —  was  then  unmarked 
by  strong  topographical  features,  for  it  was  traversed  by  no  ranges 
of  mountains,  nor  by  any  rivers  or  streams.  Shallow  depressions 
only,  marked  the  surface,  which  were  filled  with  water  from  the 
rains  and  the  melting  ice.  These  were  the  primitive  lakelets  and 
existed  before  any  definite  streams  were  formed.  Where  the  depres- 
sions were  longitudinal,  or  connected  in  chains,  they  gave  initial 
direction  to  the  courses  of  the  streams  into  which  the  surface  waters 
were  gathered,  and  carried  away  to  the  sea.  These  are  the  streams 
of  to  -  day,  and  their  ceaseless  flow,  aided  by  the  rains  and  frosts  of 
the  unnumbered  years  that  have  passed  since  then,  have  worn  their 
own  channels  down,  not  only  through  the  incoherent  drift,  but  often 
also  through  solid  stratified  rocks,  the  edges  of  which  we  see  pro- 
truding from  their  valley  -  slopes.  Thus  all  the  valleys  of  this 
region  are  valleys  of  erosion,  and  it  is  meterological  erosion  alone 
that  has  given  it  its  most  prominent  physical  features. 

As  one  stands  upon  the  broad,  level  prairies  of  Southern  Iowa, 
and  sweeps  the  well  -  defined,  ocean  -  like  horizon  with  his  level,  he 
finds  the  bubble  everywhere  resting  upon  the  cross  -  wire,  except 
where  the  distant  dark  line  of  forest  foliage  reveals  the  presence  of 
a  stream.  Approaching  this,  the  turface  becomes  undulating  like 
the  smooth  rolling  of  a  sea;  but  looking  closely  he  will  see  that 
every  depression  leads  into  a  still  deeper  one,  until  the  upper 
branches  of  the  streams  are  reached,  the  surfaces  of  which  are  often 
more  than  one  hundred  and  fifty  feet  below  the  prairie  level  from 
which  he  started;  and  the  surfaces  of  the  larger  streams  are  some- 
time a  hundred  feet  deeper  still.  The  higher  prairie  surface  of 
to  -  day  is  the  same  surface  which  was  left  by  the  retiring  waters  at 
the  close  of  the  glacial  epoch,  and  the  time  which  has  passed  since 
then  —  that  during  which  the  valleys  were  formed  —  is  called  by 
geologists  the  Terrace  epoch,  because  the  oscillations  of  the  streams 
from  side  to  side  of  their  valleys  in  the  process  of  their  erosion 
have  left  frequent  terraces  of  material  which  successively  constituted 
"  flats  "  or  "  bottoms "  bordering  the  streams,  but  which  are  now 
far  above  the  reach  of  their  highest  floods.  The  Terrace  epoch 
verges  upon  the  present  time,  because  the  same  streams  still  flow, 


REPORT  OF  STATE  GEOLOGIST.  155 

and  earthy  matter  is  still  carried  by  them  to  the  sea,  as  rapidly  per- 
haps as  it  ever  was,  although  only  occasionally  sufficient  in  amount 
to  muddy  the  water.  Thus  it  will  be  seen  how  slowly  the  mightiest 
operations  of  nature  are  performed;  for  this  most  recent  of  the 
geological  changes  has  doubtless  required  a  length  of  time  so  great 
that  the  human  mind  is  incapable  of  comprehending  it. 

In  Northern  Iowa  the  prairie  horizons  are  not  so  clearly  defined, 
as  they  are  further  to  the  southward,  and  it  was  doubtless  so  at  the 
beginning.  The  drift  also  contains  more  gravel  and  boulders  there, 
from  the  fact  that  nearly  all  of  those  materials  originating  still  farther 
to  the  northward,  their  abundance  diminished  with  the  diminishing 
force  of  the  glaciers  to  the  southward.  Numerous  irregular  rounded 
elevations  or  knobs  mark  the  surface,  between  which  are  correspond- 
ing depressions ;  not  produced,  however,  by  erosion  since  the  drift 
was  deposited,  as  the  river  valleys  were,  but  are,  like  the  knobs, 
inequalities  left  by  the  glaciers. 

Some  of  these  depressions  have  become  drained ;  some  of  them  are 
still  occupied  by  the  lakelets,  and  some  by  peat  marshes.  Streams 
are  numerous  in  Southern  Iowa  and  their  valleys  deep ;  consequently 
the  country  is  so  well  drained  that  all  trace  of  the  primitive  lakelets 
is  usually  obliterated.  But  many  of  those  streams  have  their  rise  in 
Northern  Iowa,  and  many  of  those  lakelets  still  exist  there,  because 
no  accumulation  of  water  beyond  has  sent  a  current  across  them  to 
cut  a  channel  for  their  outlet.  Lake  -  basins  are  sometimes  hollowed 
very  deeply  into  the  earth,  showing  bold  exposures  of  stratified  or 
unstratified  rocks  upon  their  shores.  But  the  lakelets  of  which  we 
we  are  speaking  had  their  origin  in  shallow  depressions  left  in  the 
surface  of  the  drift  alone  at  the  close  of  the  glacial  epoch.  By  the 
action  of  subsequent  causes  they,  in  certain  regions,  became  "  walled 
lakes,"  for  a  majority  of  them  are  as  worthy  of  that  designation  as 
those  are  of  which  the  fanciful  stories  have  been  told.  Nor  are  lakes 
of  that  character  confined  to  Iowa  alone,  but  are  known  also  in  Min- 
nesota, Wisconsin,  Michigan,  and  even  in  Connecticut,  yet  all  except 
two,  one  in  Wright  county  and  the  other  in  Sac  county,  Iowa,  seem 
never  to  have  been  favored  with  the  visits  of  an  imaginative  writer 
to  tell  fanciful  stories  of  their  associated  remains  of  human  handi- 
work. 


156  REPORT  OF  STATE  GEOLOGIST. 

It  seemed  necessary  to  make  the  foregoing  statement  of  facts  and 
the  geological  principles  which  they  involve,  before  attempting  a 
description  of  the  lakelets  themselves,  that  such  a  description  might 
thus  be  rendered  more  intelligible,  and  which  is  here  given  as  the 
result  of  long  -  continued  observation  of  sixteen  such  lakelets  in 
Northern  Iowa,  including  the  two  which  have  become  noted  as  walled 
lakes.  They  usually  occupy  an  open  prairie  region.  Sometimes 
small  groves  are  near  them,  but  trees  are  often  entirely  wanting, 
especially  since  the  settlers  mercilessly  destroy  them  for  fuel.  They 
are  from  one  to  five  miles  across,  but  always  very  shallow,  because 
the  undulations  within  which  they  rest  are  very  gentle.  None  of 
them  are  more  than  fifteen  feet  deep,  and  the  majority  are  so  shallow 
that  they  permit  a  luxuriant  growth  of  wild  rice  and  other  aquatic 
plants  from  their  bottoms  over  the  whole,  or  a  large  part  of  their 
areas,  among  which  water -fowl  find  shelter  and  abundant  food,  but 
which  renders  them  rather  uninteresting  features  of  the  landscape. 

A  true  description  of  the  so-called  walls, but  which  we  shall  term 
embankments,  will  be  best  understood  if  given  in  connection  with  a 
description  of  their  origin. 

When  a  pile  of  sand,  obtained  from  the  river  -  shore,  has  been  left 
by  the  workman  for  a  long  time  exposed  to  the  washings  of  the  rains, 
the  gravel  which  it  contains,  and  which  at  first  is  hardly  visible, 
becomes  in  some  cases  even  more  conspicuous  than  the  sand  itself, 
because  a  part  of  the  latter  has  been  wasted,  while  the  gravel 
remains.  Thus,  it  has  been  upon  an  extended  scale  with  the  drift, 
which,  as  before  stated,  is  composed  of  boulders,  gravel,  sand,  clay 
and  soil,  although  little  except  the  latter  is  usually  seen  upon  the 
prairie  and  surfaces.  Sometimes  the  drift  is  more  than  a  hundred 
feet  thick,  and  all  the  boulders  contained  in  the  whole  mass  which 
has  been  swept  out  to  form  the  valleys,  have  gradually  rolled  down 
upon  their  slopes,  and  many  of  them  into  the  streams.  For  this 
reason  we  usually  find  them  more  numerous  upon  surfaces  that  have 
suffered  erosion  than  anywhere  else.  Again,  the  ceaseless  dashing 
of  a  lakelet's  waves  stir  up  the  finer  material  beneath  its  waters  to 
be  carried  away  in  the  form  of  muddy  water  at  the  times  of  its  over- 
flow, leaving  the  boulders  and  gravel  strewn  upon  its  bed ;  while  they 
may  not  be  seen  at  all  upon  the  prairie  -  surfaces  around  them.  This 


REPORT  OF  STATE  GEOLOGIST. 

latter  fact,  being  misunderstood,  has  led  to  the  supposition  that  being 
absent  upon  those  surfaces  they  had  been  gathered  up  by  human 
hands  and  carried  to  the  shores  to  build  the  "walls,"  while  the 
truth  is,  the  embankments,  as  well  as  the  presence  of  the  materials 
of  which  they  are  composed,  are  due  to  natural  causes  alone,  and 
their  origin  is  wholly  referable  to  the  periodic  action  of  ice,  aided  in 
some  degree  by  the  force  of  the  waves. 

The  water  in  the  lakelets  is  usually  very  low  in  late  autumn,  and 
when  winter  comes  it  is  sometimes  frozen  nearly  to  the  bottom  in 
their  deepest  parts,  so  that  occasionally  all  the  fish  are  killed  by  this 
means.  The  ice  of  course  freezing  fast  to  the  boulders  as  well  as  to 
whatever  else  may  be  within  its  reach,  and  the  expansive  power  of 
from  one  to  five  miles  of  freezing  water  is  exerted  upon  them  in  a 
direction  from  the  centre  toward  the  shores  —  a  power  much  more 
than  sufficient  to  move  the  largest  boulders  upon  those  gentle  slopes. 

The  embankments  are  from  two,  to  six  feet  high,  and  from  two,  to 
twenty  feet  across  the  top  ;  and  always  separate  a  low  piece  of 
ground  from  the  lake,  because  where  the  original  shore  is  a  little 
abrupt,  and  higher  than  the  high  -  water  level,  no  embankment  is 
formed,  but  the  boulders  are  merely  thrust  against  the  shore  with 
such  force  as  to  render  it  steep,  and  often  thickly  studded  with  them. 
Meeting  no  such  obstruction  on  a  marshy  side,  the  material  thrust 
out,  accumulates  just  where  the  expansive  force  of  the  ice  is  spent. 
This  process  repeated  year  after  year,  from  age  to  age,  has  cleared 
the  bottom  of  the  lakelets  of  the  boulders  and  other  materials,  and 
piled  them  up  in  circular  ridges  upon  their  shores;  and  these  are 
the  "  walls "  which  have  excited  so  much  wonder.  It  has  been 
observed  that  the  embankments  are  heaviest  on  the  sides  opposite  the 
prevailing  winds.  This  may  be  accounted  for,  at  least  in  part,  by 
the  fact  that  the  ice  being  burthened  with  the  material  to  which  it 
had  frozen  fast  would  thus  be  floated  against  those  shores  when  the 
spring  floods  had  raised  the  water  of  the  lakes ;  and  in  part  also  by 
the  further  fact  that  the  dashing  of  the  waters  would  be  most  con- 
stant against  those  shores. 

Thus  it  will  be  seen  that  whatever  was  originally  upon  the  bottom, 
whether  boulders,  gravel,  sand  or  mud,  has  been  carried  to  the  shore, 


158  REPORT  OF  STATE  GEOLOGIST. 

and  we  find  the  embankment  composed  of  all  these  materials  arranged 
in  perfectly  natural  disorder.  If  boulders  were  numerous  the 
embankment  is  largely  composed  of  them.  If  sand  prevailed,  a 
broadly  rounded  embankment  is  formed,  just  such  as  we  should 
expect  from  such  material;  and  where  a  peat  marsh  extends  out 
into  the  land  an  embankment  of  turf  is  thrown  up  at  the  water's 
edge  which  being  supported  by  living  rootlets,  is  frequently  high 
and  very  narrow.  The  latter  are  somewhat  numerous  and  are  often 
called  beaver -dams;  but  this  is  also  a  misconception,  because 
beavers  never  attempt  to  dam  still  waters.  They  dam  running 
streams  to  obtain  ponds  of  still  water. 

Thus  we  see  that  the  same  natural  force  placed  the  boulders  in 
the  embankments  that  brought  them  down  from  their  northern  homes, 
namely,  the  expansive  power  of  ice.  The  embankments  are  really 
very  interesting  natural  objects,  and  it  is  not  strange  that  they  have 
attracted  attention ;  but  with  a  correct  knowledge  of  the  action  of 
natural  forces,  it  is  difficult  to  understand  how  any  one  could  suppose 
that  human  hands  had  any  thing  to  do  with  their  construction. 
There  is  certainly  nothing  in  the  arrangement  of  the  materials  that 
indicates  such  an  origin,  and  the  liveliest  imagination  refuses  to 
suggest  any  object  for  which  human  beings  could  have  desired  them, 
or  to  point  out  any  evidence  of  intelligence  in  their  location  and 
plan. 

If  its  crust  should  remain  perfectly  stable  long  enough,  the  earth 
would  become  nearly  a  perfect  sphere  by  the  disintegration  of  its 
exposed  substance,  and  the  levelling  force  of  gravitation.  It  is  true 
that  its  inequalities  of  surface  are  now  very  insignificant  compared 
with  the  vastness  of  its  bulk ;  but  in  such  a  case  there  would  be  no 
mountains,  no  islands,  no  continents.  All  would  be  an  endless  and 
shoreless  sea.  The  erosion  of  the  river  valleys,  and  the  consequent 
drainage  of  a  majority  of  the  primitive  lakelets  may  be  regarded  as 
the  first  steps  in  this  levelling  process,  after  the  glaciers  had  ceased 
from  the  Great  Valley ;  for  its  post  -  glacial  geology  seems  to 
warrant  no  subdivision  into  epochs  such  as  are  made  for  other  regions; 
therefore  the  whole  is  here  referred  to  the  Terrace  epoch.  Long 
before  this  levelling  process  can  approach  completion  other  elevations 
and  depressions  will  be  formed  upon  the  changing  surface,  just  as  the 


REPORT  OF  STATE  GEOLOGIST. 

present  seas  and  continents  occupy  the  places  of  other  seas  and  other 
lands  that  existed  long  before  them ;  because  perfect  stability  of  the 
earth's  surface  never  has  existed,  and  probably  never  will  exist. 
See  then  how  small  a  part  of  such  a  result  has  been  accomplished 
even  by  the  erosion  of  the  valleys  of  the  great  Mississippi  and  its 
branches.  A  part  of  the  primitive  lakelets,  and  a  part  of  the 
original  surface  of  the  drift  still  remain  almost  unchanged  since  their 
formation.  The  prairies  have  still  their  ocean  -  like  surfaces,  and 
the  greatest  change  the  lakelets  have  undergone  in  that  immense 
lapse  of  time  is  the  formation  of  their  insignificant  embankments,  if 
aught  in  nature  may  be  called  insignificant. 

Let  us  look  a  little  to  what  has  been  accomplished  by  erosion  in 
the  Great  Valley  *  during  the  Terrace  epoch,  as  before  defined,  and 
we  will  find  enough  to  excite  our  wonder  and  admiration. 

Along  the  courses  of  what  are  now  the  Mississippi  and  Missouri 
Rivers,  large  depressions  formerly  existed,  which  formed  lake  -  like 
expansions  of  those  rivers.  Thus,  after  the  Mississippi  had  made 
for  itself  a  definite  valley,  but  before  it  had  cut  its  channel  nown  to 
its  present  level  through  the  rocky  obstruction  at  the  Keokuk  rapids, 
that  portion  of  it  which  borders  a  large  part  of  the  eastern  side  of 
Iowa  was  little  else  than  a  lake  which  averaged  about  five  miles  wide 
and  filled  the  space  between  what  are  now  the  bluffs  that  border  each 
side  of  its  broad,  flat  valley. 

This  is  proven  by  the  existence  there  of  the  terraces,  composed  of 
very  fine  sedimentary  material,  such  as  could  have  been  deposited 
only  in  comparatively  still  waters,  and  also  by  the  existence  in 
that  sediment  of  shells  which  inhabit  still  waters  only  —  the  same 
species  which  now  inhabit  fresh  -water  lakes.  River  shells,  such. as 
now  exist  in  the  river,  are  found  on  the  sides  of  the  bluffs  near  the 
rapids  at  a  hight  of  seventy  feet  above  the  present  high  -  water  mark ; 
and  since  such  beds  of  shells  exist  only  at  low  -  water  mark  when 
alive,  upward  of  eighty  feet  must  be  estimated  as  the  hight  of  the 
river  above  its  present  level  at  the  time  they  lived. 

It  will  be  observed  that  river,  and  not  lacustrine  shells,  are  found 

*  it  will  be  observed  that  the  word  valley  is  used  with  two  separate  significations 
—  one  applied  to  the  hydrographic  basin  drained  by  a  certain  principal  stream 
and  its  tributaries,  and  the  other  to  the  depression  occupied  by  any  particular 
stream,  and  which  its  own  waters  have  cut  out  of  the  general  surface. 


1  60  REPORT  OF  STATE  GEOLOGIST. 

near  the  rapids.  This  is  accounted  for  by  the  fact  that  the  obstruc- 
tion which  caused  them,  being  a  flinty  formation,  and  not  so  easily 
disintegrated  as  the  other  rocks  over  which  the  river  runs,  has  existed 
as  such  from  it  its  earliest  history.  Consequently  the  water  there 
always  had  a  considerable  current,  while  further  to  the  northward 
there  was  too  little  current  to  produce  a  congenial  habitat  for 
those  shells.  The  estimated  eighty  feet  is  doubtless  only  a  part  of 
the  actual  hight  from  which  the  erosion  of  the  Mississippi  Valley 
has  reached,  because  it  now  averages  about  two  hundred  feet  deep 
from  the  general  prairie  surface.  Thus  we  see  that  when  that 
lake -like  expansion  existed  in  the  Mississippi  river,  its  valley  had 
already  been  eroded  to  considerable  depth,  and  the  Terrace  epoch 
was  well  advanced.  Bat  on  the  other  side  of  the  State  we  have 
proof  of  the  existence  in  the  early  part  of  that  epoch  of  a  lake 
which  was  larger  and  deeper  than  Lake  Erie.  This  proof  consists 
principally  in  the  presence  there  of  a  peculiar  lacustrine  deposit, 
extending  at  least  from  the  Big  Sioux  to  the  mouth  ot  the  Kansas 
river,  and  from  twenty  to  thirty  mibs  on  each  side  of  the  Missouri 
river,  through  which  the  latter  has  cut  its  present  valley,  in  some 
places  to  a  depth  ot  more  than  two  hundred  feet,  before  it  reached 
the  drift  which  was  deposited  there  during  the  Glacial  epoch.  That 
material  is  known  to  have  been  deposited  in  fresh  water,  because 
only  fresh-water  shells  are  found  in  it,  and  they  are  found  in  it  from 
top  to  bottom.  It  is  known  to  have  been  deposited  in  still  water, 
because  the  same  kinds  ot  shells  are  now  living  in  still  water  only, 
and  because  the  wrhole  deposit  is  a  fine,  homogeneous  material,  with- 
out sand,  gravel,  boulders,  or  any  thing  else,  except  what  would  have 
been  deposited  in  a  lake  of  muddy  water. 

It  has  been  claimed  by  a  few  geologists,  that  at  the  close  of  the 
Glacial  epoch  a  shallow  fresh -water  lake  occupied  the  whole 
hydrographic  basin  of  the  Mississippi,  and  that  the  fine  soil  and 
subsoil  of  the  prairies  and  other  lands  of  the  whole  region,  as  well 
as  the  peculiar  deposit  just  referred  to,  are  identical  in  their  forma- 
tion, and  had  their  origin  in  one  and  the  same  broad  lake.  Upon 
this  hypothesis  some  have  accounted  for  the  origin  of  the  prairies 
and  for  the  absence  of  trees  upon  them,  but  the  fact  is,  prairies  exist 
upon  both  these  deposits;  and  it  would  require  direct  effort 


REPORT  OF  STATE  GEOLOGIST. 

to  keep  all  kinds  of  indigenous  trees  from  encroaching  upon 
kinds  of  indigenous  trees  from  encroaching  upon  the  prairies  if  there 
were  no  annual  fires. 

It  is  not  improbable  that  such  a  wide -spread  sheet  of  fresh  water 
did  exist  at  that  time,  and  that  a  large  part  of  the  sedimentary 
material  that  composes  our  soil  and  subsoil  had  such  an  origin.  But 
that  is  widely  different  in  physical  characters  from  the  deposit  under 
discussion,  which  evidently  had  a  different,  as  v.  ell  as  a  subsequent 
origin.  These  circumstances  seem  to  leave  no  room  to  doubt  that  a 
well  -  defined  lake  existed  there  after  the  continent  was  in  great  part 
dessicated,  but  before  the  great  rivers  had  cut  their  valleys  down  to 
any  considerable  depth. 

The  lake,  although  so  large  and  deep,  was  doubtless  filled  with  sedi- 
ment to  the  general  prairie  level  within  a  comparatively  short  time 
after  the  glaciers  ceased,  just  as  the  sediment  of  the  same  river 
which  then  flowed  into  and  from  it,  now  speedily  fills  the  reservoirs 
of  the  St.  Louis  water  -  works,  so  that  they  must  often  be  re -excav- 
ated. Just  as  the  same  river  would  now  fill  with  the  same  kind  of 
sediment,  any  depression,  however  large,  if  such  existed  in  its 
course. 

The  great  Northern  lakes  are  not  thus  filled,  because  their  tribu- 
tary streams  are  pure ;  and  their  streams  are  pure  because  they  flow 
over  geological  formations  that  are  not  easily  disintegrated ;  while 
the  main  tributary  of  that  ancient  lake — the  Missouri  river  —  is 
even  now  one  of  the  muddiest  streams  on  the  globe.  In  the  earlier 
portion  of  the  Terrace  epoch,  it  was,  if  possible,  more  so;  for  then, 
as  now,  it  gathered  up  its  sediment  from  that  broad  region  occupied 
by  the  friable  rocks  of  the  Tertiary  and  Mesozoic  ages,  stretching 
far  away  towards  the  Rocky  Mountains,  at  that  time  strewn  with  the 
grindings  fresh  from  those  "mills  of  the  gods"  —  the  glaciers. 

The  formation  of  the  basin  in  which  the  lake  rested  is  known  to 
have  taken  place  during  the  glacial  period,  because  the  drift  with  its 
striated  boulders  now  covers  its  bottom  beneath  the  lacustrine 
deposit,  and  because  the  cutting  out  of  the  river  valley  has  exposed, 
in  a  number  of  places,  the  stratified  rocks  which  the  drift  rests  upon, 
the  surfaces  of  which  are  scored  and  striated  by  the  moving  glaciers 

of  that  period.     It  is  known  that  the  filling  of  the  lake  with  sediment 
21 


1(52  REPORT  OF  STATE  GEOLOGIST. 

occurred  in  the  early  part  of  the  Terrace  epoch,  because  it  was 
filled  up  even  -with  the  prairie  surfaces,  which  would  not  have  been 
done  if  the  Missouri  river  had  first  eroded  its  valley  to  any  consid- 
erable depth  below  the  lake.  We  know  that  the  lake  was  so  far  filled 
with  sediment  before  it  was  drained,  that  it  was  little  else  than  a 
marsh,  because  the  top  of  that  deposit  of  sediment  is  now  nearly 
even  with  the  higher  prairie  surfaces,  and  because  the  river  bluffs 
which  it  forms  are  as  high  as  those  formed  of  the  usual  materials,  — 
the  drift  and  stratified  rocks. 

The  physical  characters  of  this  lacustrine  deposit  are  so  peculiar 
that  they  attract  the  attention  of  every  person  who  becomes 
acquainted  with  it,  although  a  stranger  might  pass  over  the  forma- 
tion without  observing  more  than  its  peculiar  outline  of  bluffs.  It 
is  perfectly  uniform  in  character  and  color  from  top  to  bottom,  and 
a  hundred  miles  of  distance  show  no  more  difference  than  a  hundred' 
feet.  It  is  of  a  slightly  yellowish  ash  color,  except  where  rendered 
darker  by  decaying  vegetation,  very  fine,  not  sandy  and  yet  not 
adhesive.  At  the  surface  it  makes  excellent  soil,  and  is  just  as  fer- 
tile if  obtained  at  a  depth  of  two  hundred  feet.  It  is  easily  exca- 
vated by  the  spade  alone,  and  yet  it  remains  so  unchanged  by  the 
atmosphere  and  frost  that  wells  dug  in  it  require  to  be  walled  only 
to  a  point  just  above  the  water  -  line,  while  the  remainder  stands  so 
securely  without  support  that  the  spade  -  marks  remain  upon  it  for 
many  years.  Road  -  embankments,  upon  the  sides  of  excavations, 
stand  like  a  wall,  showing  the  names  of  ambitious  carvers  long  after 
an  ordinary  bank  of  earth  would  have  disappeared.  As  that  part  of 
the  valley  of  the  Missouri  river  below  the  lake  was  deepened  during 
the  Terrace  epoch  by  the  natural  process  of  erosion,  the  peculiar 
material  which  its  own  waters  had  previously  deposited,  offered  little 
obstruction  to  that  process,  but  was  readily  swept  out  again  as 
muddy  water,  and  sent  on  its  way  to  the  sea.  Thus  no  more  of  it 
was  cut  out  than  served  to  form  the  valley,  which  is  from  four  to  six 
miles  wide,  while  the  larger  part  remained,  forming  the  bluffs  and 
extending  far  inland  from  the  river.  The  tributary  streams  which 
at  first  emptied  into  the  lake,  now  traversed  its  ancient  bed  of  sedi- 
ment to  the  river,  and  cut  down  their  own  valleys  to  meet  it.  The 
sides  of  these  valleys,  where  they  traverse  that  sedimentary  deposit 


REPORT  OF  STATE  GEOLOGIST. 

are  steep  like  the  river  bluffs,  and  the  streams  being  smaller,  their 
valleys  are  narrow  and  very  deep.  This  is  particularly  true  of  all 
those  Iowa  streams  that  empty  into  the  Missouri  river  above  Council 
Bluffs,  and  they  thus  present  great  obstacles  to  the  construction  of 
lines  of  railway  directly  east  and  west  through  that  State.  For 
this  reason,  and  for  the  purpose  of  connecting  with  the  great 
Pacific  Railway  at  Omaha,  the  more  northern  of  those  lines  are 
diverging  to  the  southward  down  the  valleys  of  the  streams,  instead 
of  crossing  them,  so  that  passengers  will  pass  dry-shod  through  the 
bed  of  that  ancient  lake,  although  many  fathoms  beneath  the  level 
at  which  its  waters  used  to  rest. 

The  peculiar  outline  of  the  bluffs  along  the  Missouri  river  valley 
is  one  of  the  most  interesting  features  of  this  remarkable  deposit. 
As  one  views  them  in  the  distance,  and  in  their  nakedness,  for  they 
are  often  entirely  destitute  of  trees,  towering  up  from  the  level  bot- 
tom land,  sometimes  more  than  two  hundred  feet  in  hight ;  so  steep 
in  some  places  that  a  man  can  not  climb  them,  he  can  hardly  rid 
himself  of  the  idea  that  they  are  supported  by  a  framework  of  rocks 
as  other  bluffs  are.  Yet  not  a  rock  or  pebble  of  any  kind  or  size 
exists  above  their  base  of  drift,  except  a  few  calcareous  concretions 
which  were  formed  from  the  limy  water  that  now  percolates  through 
the  whole  mass.  The  form  and  arrangement  of  their  numerous 
rounded  prominences  sometimes  present  views  of  impressive  beauty 
as  they  stretch  away  in  the  distance,  or  form  bold  curves  in  the  line 
of  hills.  A  few  miles  below  the  city  of  Council  Bluffs  they  present 
a  full  crescentic  view  to  the  westward,  with  the  broad  Missouri  bot- 
tom stretching  miles  away  from  their  base  to  the  river.  Their  only 
vegetation  here  is  a  covering  of  wild  grasses,  and  as  the  mound  -  like 
peaks  and  rounded  ridges  jut  above  each  other,  or  diverge  in  various 
directions  while  they  recede  backward  and  upward  to  the  higher 
lands,  the  setting  sun  throws  strange  and  weird  shadows  across  them, 
producing  a  scene  quite  in  keeping  with  that  wonderful  history  of  the 
past  of  which  they  form  a  part. 

THE  IOWA  COAL-FIELD. 

The  character  of  the  field  -  work  of  the  survey  has  thus  far  been 
that  of   a   general  reconnoisance,   so   that   the  boundaries   of  the 


164  REPORT  OF  STATE  GEOLOGIST. 

coal  -  field  has  not  been  determined  with  precision.  So  far  as  the  eas- 
tern and  northern  borders  are  concerned,  they  were  at  least  approxi- 
mately determined  by  the  former  geological  survey.  As  that  report 
may  not  be  possessed  by  all  into  whose  hands  this  shall  fall,  a  descrip- 
tion of  it,  somewhat  modified,  is  here  given. 

Draw  a  line  on  the  map  of  Iowa  from  the  southeast  corner  of  Van 
Buren  county  directly  .northward  until  it  touches  the  south  line  of 
Washington  county;  thence  northwestward,  keeping  six  or  eight  miles 
to  the  northward  of  North  Skunk  river,  to  the  south  line  of  Marshall 
county,  a  little  west  of  its  centre ;  thence  to  a  point  three  or  four 
miles  northeastward  from  Eldora,  Hardin  county ;  thence  to  Webster 
City,  Hamilton  county:  thence  to  Fort  Dodge,  Webster  county, —  and 
you  have  approximately  the  eastern  and  northern  borders  of  the 
productive  coal  -  field  of  Iowa.  It  is  not  claimed  that  all  the  coal  of 
the  State  exists  southward  and  westward  of  this  line,  for  it  is  already 
known  to  exist  in  Lee,  Henry  and  Washington  on  the  other  side  of 
it  as  well  as  in  Muscatine  and  Scott  counties,  but  it  is  believed  that 
very  little  coal  will  be  found  outside  of  the  line  thus  designated. 

Indications  of  coal  are  often  found  to  the  northward  and  eastward 
of  this  line,  but  although  the  strata  discovered  are  really  coal- 
measure  strata,  yet  they  are  small  isolated  deposits,  called  outliers 
by  geologists,  too  small  and  too  thin  to  afford  a  workable  bed  of  coal. 
An  exception  to  this  rule  is  the  large  outlier  extending  from  Musca- 
tine almost  to  Davenport,  where  a  small  bed  of  coal  has  been  worked 
several  years.  A  number  of  other  small  outliers  have  been  discovered 
in  Johnson,  Louisa,  Benton,  and  doubtless  may  be  also  found  in  other 
counties.  The  dip  of  the  strata  (the  general  dip,  not  the  local  dip  ; 
the  general  dip  is  too  slight  to  be  perceptible  to  the  eye),  being  to 
the  southward  and  westward,  it  follows  that  at  the  northern  and 
eastern  borders  ot  the  coal  -  field  it  would  have  a  thinner  develop- 
ment than  further  within  the  field.  Thus  it  will  be  seen  that  one 
encounters  greater  hazard  in  exploring  for  coal  along  its  thinning  -  out 
border  than  he  would  within  the  main  portion ;  yet  some  instances 
are  known  of  the  existence  of  good  mines  very  near  the  well  -  defined 
border. 

To  the  westward,  and  southward  of  the  Des  Moines  river,  it  is  not 
known  how  far  the  productive  coal  formation  actually  extends,  for  it 


REPORT  OF  STATE  GEOLOGIST. 

passes  beneath  the  unproductive  series  of  coal  -  measure  strata,  and 
beneath  the  heavy^  deposits  of  drift  which  are  not  deeply  cut  along 
the  dividing  ridge  of  the  State  as  they  are  in  other  parts. 

Some  coal  has  been  found  in  Webster,  Boone,  Dallas,  Madison, 
Lucas  and  Wayne  counties,  west  of  the  Des  Moines  river,  beside  the 
thin  bed  in  the  upper  coal  -  measures,  along  the  Nodaway  river ; 
while  Polk,  Warren,  Marion,  Monroe,  Mahaska,  Wapello,  Appanoose, 
Davis  and  Van  Buren,  lying  wholly  or  partly  upon  the  west  side,  are 
among  the  most  important  coal  counties.  Thus  far,  however,  the 
greater  part  of  our  coal  is  obtained  northward  and  eastward  of  the 
Des  Moines  river.  For  further  remarks  upon  the  probabilities  of 
finding  coal,  by  deep  mining  in  the  western  part  of  the  State,  see 
introductory  chapter. 

In  that  part  of  the  productive  coal  -  field  thus  far  explored,  there 
is  satisfactory  evidence  that  no  very  deep  mining  will  be  necessary 
in  any  part  of  it.  This  is  inferred  from  the  fact  that  the  larger 
streams  are  found  to  have  cut  their  valleys  down  through  all  the 
coal  -  measure  strata  to  the  sub  -  carboniferous  limestone. 

The    distance    down  to  this  limestone  from  some  of    the  higher 

-  surfaces  in  this  portion  of  the  coal  -  field  may  sometimes  be  as  great 

as  three  hundred  feet,  but  it  probably  will  not  exceed  this    depth 

anywhere  to  the  northward  and  eastward  of  the   Des   Moines  river, 

and  may  usually  be  expected  at  a  much  less  depth. 

Although  the  known  area  of  the  productive  coal  -  field  of  Iowa,  as 
thus  defined,  is  smaller  than  some  have  supposed,  yet  it  will  be  seen 
that  its  area  is  equal  to  that  of  the  whole  State  of  Massachusetts 
beside  which,  it  is  expected  that  this  area  will  be  extended  to  the 
westward  by  the  discovery  of  coal  at  an  increasing  depth  beneath 
the  surface. 

SOIL,  VEGETATION,  &c. 

There  is  probably  not  an  equal  area  upon  the  earth  that  contains 
proportionally  less  untillable  land  than  does  the  State  of  Iowa. 

By  far  the  greater  part  of  it  is  of  drift  origin,  all  of  which  is 
scarcely  less  fertile  than  the  rich  alluvial  and  lacustrine  soils  found 
bordering  the  rivers. 

The  drift  deposit  is    very   deep  in  all  parts  of   the   State,    and 


166  REPORT  OF  STATE  GEOLOGIST. 

consists  of  so  much  fine  material  that  the  boulders,  gravel  and  sand  it 
usually  contains  are  almost  .nowhere  the  least  obstruction  to  farming 
operations.  It  has  been  estimated  by  some  that  seven  -  eighths  of  the 
surface  of  the  State  are  occupied  by  the  prairies.  These  prairies 
are  always  fertile  and  exist  upon  all  varieties  of  soil,  and  their  origin 
can  not  therefore  be  due  to  any  one  of  them.  The  greater  part  of 
the  forest  trees  are  found  in  the  vicinity  of,  and  skirting  the  borders 
of  the  streams ;  and  there  is  little  variation  in  the  kinds  of  trees 
which  compose  the  forests  throughout'  the  whole  State  that  can  be 
ascribed  to  a  difference  of  climate.  Its  principal  forest  trees  are 
several  kinds  of  oaks,  black  and  white  walnut,  hickories  and  pecan, 
white  and  sugar  maple,  cottonwood  and  aspen,  linden,  red  birch, 
horse  chesnut,  box  elder,  ash,  honey  locust,  red  and  slippery  elm, 
&c.  It  is  a  notable  fact  that  alt  these  trees  will  grow  thriftily  upon  all 
varieties  of  our  prairie  soil;  even  those  whose  chosen  habitat  is  in  the 
neighborhood  of  the  streams. 

Thus  far  no  chestnut  nor  beech  have  been  found  in  the  State,  but 
a  few  of  the  former  have  been  introduced.  Of  introduced  trees, 
the  black -locust  succeeded  well  for  many  years  and  until  it  was 
attacked  by  the  borers  in  1863,  since  which  time  almost  all  the  trees 
have  been  killed  by  this  means.  The  osage  -  orange  succeeds  well  in 
at  least  the  southern  half  of  the  State,  where  some  as  perfect  and 
effective  hedges  of  it  as  one  could  desire  have  been  in  use  a  number 
years,  and  its  use  is  rapidly  increasing.  It  has  not  yet  been  fully 
tested  in  the  northern  part  of  the  State.  The  prairies  are  always 
covered  with  rank,  and  usually  nutritious  grasses,  beside  a  great 
variety  of  other  plants  which  differ  little  in  species  throughout  the 
State.  Of  shrubbery  there  is  almost  as  little  difference ;  hazel, 
wild -plum  and  crab -apple  being  the  principal  kinds  everywhere. 
Of  edible  berries,  the  blackberry,  raspberry  and  strawberry  are  the 
chief.  The  common  cranberry  has  not  thus  far  been  observed  in  the 
State,  although  the  so  -  called  high  -  bush  cranberry  is  occasionally 
found  in  the  northern'  part.  It  is  not  properly  a  cranberry,  for  it 
has  only  a  single  seed  like  the  black  haw,  to  which  it  is  closely 
related,  and  which,  except  in  the  color  of  its  fruit,  it  much  resembles. 

The  adaptability  of  our  soil  to  grapes,  all  kinds  of  orchard  fruits, 


REPORT  OF  STATE  GEOLOGIST. 

grasses  and  staple  cereals,  is  too  well  and  widely  known  to  need  men- 
tion at  this  time. 

COAL  AT  DES  MOINES. 

No  connected  observations  have  yet  been  made  in  Polk  county, 
but  while  making  visits  to  Des  Moines  on  business,  several  of  the 
coal  -  mines  in  the  vicinity  of  the  city  have  been  examined.  These 
are  those  of  Messrs.  Redhead  &  Vincent,  just  above  the  city  on  the 
west  side  of  the  Des  Moines  River,  and  two  or  three  on  land  of  Mr. 
C.  C.  Van,  almost  within  the  city,  on  the  south  side  of  Raccoon 
River. 

The  most  that  can  now  be  said  of  these  mines  is  that  the  coal  of 
all  is  of  good  quality,  much  of  it  excellent.  There  is  no  doubt  that 
the  high  lands  surrounding  the  city  are  all  underlaid  by  a  bed  of 
coal,  but  it  is  doubtless  better  and  more  workable  at  some  points  than 
others.  It  is  at  present  believed  that  the  coal  -  beds  now  worked  at 
Des  Moines  belong  to  the  upper  part  of  the  lower  coal  -  measure 
series,  in  which  opinion  Mr.  St.  John  concurs,  who  has  also  visited 
them,  and  has  also  traced  out  the  geology  of  the  Raccoon  river 
region  with  much  care.  If  this  opinion  is  correct,  it  is  not  improba- 
ble that  other  beds  of  coal  exist  beneath  the  one  now  worked ;  and  if 
our  present  estimate  of  the  thickness  of  the  lower  coal  -  measure 
series  of  strata  is  correct,  a  shaft  commenced  in  the  valley  would 
pierce  all  those  strata  by  reaching  a  depth  of  from  one  hundred  and 
fifty  to  two  hundred  feet.  It  will  of  course  be  seen  that  we  infer 
that  some  of  the  mines  worked  in  Marion  and  otlur  counties  are  in 
beds  which  belong  in  the  series  below  the  Des  Moines  coal,  yet  these 
beds  may  or  may  not  exist  beneath  those  at  Des  Moines. 

COLLECTIONS. 

During  the  progress  of  the  work,  important  collections  of  fossils, 
minerals,  rocks,  coals,  &c.,  have  been  made,  the  greater  part  of  which 
yet  remain  at  the  rooms  in  Iowa  City  for  want  of  time  to  distribute 
them  as  the  law  provides ;  yet  some  excellent  selections  have  already 
been  sent  to  the  following  -  named  Institutions,  and  their  receipts 
taken  therefor,  viz  :  State  Agricultural  College,  four  boxes ;  Cornell 
College,  one  box ;  Iowa  College,  one  box ;  Tabor  College,  one  box. 


168  REPORT  OF  STATE  GEOLOGIST. 

These  specimens  have  all  been  carefully  ticketed  and  plainly- written 
catalogues  sent  with  each  collection,  so  that  by  observing  the  number 
written  upon  the  small  ticket  which  is  pasted  upon  each  specimen, 
and  the  corresponding  number  in  the  accompanying  catalogue,  its 
name,  locality,  and  geological  position  will  all  be  known.  A  com- 
plete record  of  all  is  kept  in  the  office,  so  that  in  case  of  the  loss  of 
the  catalogue,  it  can  be  restored  by  writing  to  the  office  and  sending 
a  list  of  the  numbers  upon  the  specimens. 

Every  specimen,  great  and  small,  receives  this  small  ticket,  about 
a  quarter  of  an  inch  in  diameter,  as  soon  as  they  are  unpacked  at 
the  office  and  washed,  and  the  locality  and  geological  position  at  least 
are  immediately  recorded,  so  that  whatever  disarrangement  they  may 
afterward  suffer,  so  long  as  the  tickets  remain  pasted  upon  them, 
their  history  and  character  can  always  be  known. 

Thus  far  the  collections  have  been  made  principally  from  the 
upper,  middle  and  lower  coal  -  measures,  the  sub  -  carboniferous,  and 
part  of  the  lower  Silurian  rocks.  Beside  this,  the  specimens  con- 
sist chiefly  of  coal  from  different  parts  of  the  coal-field;  grey,  white 
and  fibrous  gypsum  from  Fort  Dodge ;  sulphate  of  strontia  from  Fort 
Dodge  ;  geodes  from  Bentonsport;  &c.,  &c. 

While  examining  the  collections  during  the  winter  of  1866-7, 
we  found  among  them  fourteen  or  fifteen  species  and  three  new 
genera  which  were  new  to  science.  These  have  been  described  under 
the  authorship  of  White  and  St.  John,  and  published  gratuitously  by 
the  Chicago  Academy  of  Science,  the  survey  receiving  credit  for 
priority  of  labor.  The  new  genera  referred  to  are  Meekella,  Crypta- 
canthia,  and  Tomoceras,  the  following  being  the  full  list : 

Amplexus  fragilis Keokuk  limestone. 

Aulosteges  spondyliformis Upper  coal  -  measures. 

Axophyllum  rudis Upper  coal  -  measures. 

Beyrichia  petrif actor St.  Louis  limestone. 

Beyrichia  foetoida Upper  coal  -  measures. 

Crania  modesta Upper  coal  -  measures. 

Cryptacanthia  compact  a Upper  coal-measures. 

Cryptoceras  Springeri Upper  coal  -  measures.    > 

Cythere  simplex St.  Louis  limestone. 


REPORT  OF  STATE  GEOLOGIST. 

Hydreionocrinus  verrucosus Upper  coal  -  measures. 

MeeJcella  striatocostata  (Cox  sp.) Upper  coal  -  measures. 

Nautilus  divisus Upper  coal  -  measures. 

Pinna  Hinrichsiana St.  Louis  limestone. 

Tomoceras  Gillianum Upper  coal  -  measures. 

Besides  the  above,  numerous  specimens  of  a  small  object  was  found 
in  the  upper  coal  -  measure  marlites,  which  is  supposed  to  belong  to 
the  Protozoan  genus  Amphistegina,  specimens  of  which  have  been 
sent  to  Dr.  William  B.  Carpenter  of  England  for  examination,  since  no 
one  in  our  country  is  known  to  be  giving  especial  study  to  those 
unusual  objects. 


22 


LETTERS 


OF 


MR.   O.  H.   ST.  JOHN 

V 

ASSISTANT   STATE    GEOLOGIST, 


GEOLOGY  OF  THE  RACCOON  RIVER  REGION, 


During  the  past  season,  through  the  kindness  of  the  Director  of 
the  Geological  Survey,  the  writer  was  permitted  to  spend  a  consider- 
able portion  of  the  autumn  in  the  country  traversed  by  the  Raccoon 
rivers,  with  the  view  of  studying  the  stratigraphical  geology  of  that 
section  of  the  State.  The  counties  of  Polk,  Dallas,  Guthrie,  Greene 
and  Carroll  held  out  important  inducements  to  that  end,  and  the 
result  of  the  season's  work  was  satisfactory  in  a  high  degree.  The 
counties  lying  to  the  southward  and  bordering  upon  those  above 
mentioned,  had  been  already  examined,  and  their  geological  struc- 
ture made  known  through  the  labors  of  Dr.  White  during  the  pre- 
vious season.  But  heretofore  little,  I  may  say  nothing,  was  known 
of  the  character  of  the  strata  in  the  country  drained  by  the  Rac- 
coon rivers,  save  that  they  were  coal  -  bearing.  Their  relations  to 
the  well  -  developed  upper  coal  -  measures  found  along  the  North, 
Middle  and  South  rivers,  in  Madison  and  adjoining  counties,  and  to 
the  lower  coal-measures  which  are  exposed  on  the  Des  Moines, 
remained  to  be  determined.  Nor  was  the  nature  of  the  coal  -  beds 
themselves  any  better  known  beyond  the  localities  where  they  made 
their  appearance  ;  and  their  relations  to  one  another  were  unex- 
plained. Indeed,  the  field  was  new,  and  gave  promise  of  valuable 
results  in  behalf  of  the  economic  interests  of  the  State. 

To  facilitate  our  review  of  the  ground,  I  will  at  once  introduce  a 
vertical  section  of  the  strata  with  which  we  have  to  deal,  presenting 
only  such  details  as  shall  be  essential  to  our  purpose. 


171 


REPORT  OF  STATE  GEOLOGIST. 
COAL-MEASURES. 


Sandy  shales  and  sandstones. 


50  FEET. 


70  TO  90  FEET. 


5  FEET. 


5  TO  10  FEET. 


30  TO  50  FEET. 


Black  fossiliferous  shales  and  sandy  shales,  5  to  10  ft. 
I  COAL  C. 


Clays,  with,  layers  of  compact,  impure,  fossiliferous 
limestone,  40  feet  and  upwards. 


Lower  black  shales  of  upper  group. 
Clays,  arenaceous  shales  and  sandstone. 
I  COAL  B. 


Clays,  arenaceous  shales  and  bands  of  micaceous 
sandstone:  towards  upper  part,  layers  of  impure 
fossiliferous  limestone,  and  locally  developed  black 
shales  — 70  to  90  feet. 


Layers  of  argillaceous,  fossiliferous  limestone. 


Black  shale,  clays,  impure  limestone  band. 
I  COAL  A. 


Variegated  clays,  with  nodular  bands  and  arena- 
ceous layers  —  30  to  50  feet. 


20  TO  45  FEET. 


10  TO  15  FEET. 


Sandstone,  20  to  45  feet. 


Argillaceous  and  arenaceous  shales,  10  to  15  feet. 

Des  Moines  Coal,  3  to  5  feet. 
Concretionary  sandy  shales. 


REPORT  OF  STATE  GEOLOGIST.  175 

It  will  be  observed  from  the  section  that  we  have  all  three  of  the 
coal -measure  series  represented  in  this  region,  but  of  the  lower  and 
upper  measures  only  their  upper  and  lowermost  members  are  acces- 
sible. The  middle  coal-measures,  however,  here  attains  its  full 
development,  and  it  is  with  this  division  our  attention  shall  be 
mainly  occupied. 

MIDDLE  COAL-MEASURES. 

The  middle  series  of  coal  -  measures,  as  developed  in  this  part  of 
the  State,  may  be  sub  -  divided  into  three  groups,  each  of  which 
possesses  its  own  peculiar  lithological  characters  in  distinction  from 
the  other  groups.  The  lower  group  has  a  thickness  of  from  forty  to 
seventy  feet,  the  middle  one  eighty  to  one  hundred  feet,  and  the 
and  the  upper  groups,  probably,  upward  of  fifty  feet ;  making  the 
average  thickness  of  the  middle  series  about  two  hundred  feet. 
Towards  the  top  of  each  of  the  groups  the  deposition  of  carbona- 
ceous matter  took  place,  forming  as  many  distinct  coal  -  horizons. 
The  upper  bed,  coal  C,  is  the  most  valuable  one  of  the  middle  series. 
Its  thickness  varies  between  fifteen  and  thirty  inches,  and  is  a  work- 
able bed.  It  is  overlaid  by  two  to  four  feet  of  dark  shales, 
abundantly  charged  with  fossil  remains  which  serve  to  distinguish 
this  coal  horizon  from  any  of  its  associates.  At  the  base  of  the 
upper  group  a  well  -  marked  carbonaceous  bed  is  found,  but  it  seldom 
presents  any  coal,  though  the  highly  carbonaceous  black  shale, 
capped  by  a  single  layer  of  compact  argillaceous  rock,  is  always  met 
with  wherever  it  has  not  been  denuded.  A  bed  of  sandstone  five  to 
ten  feet  thick,  forms  the  upper  bed  of  the  middle  group,  immediately 
beneath  which  the  second  carbonaceous  horizon,  coal  B,  occurs. 
This  bed  is  very  variable  in  thickness,  ranging  from  one  inch  to  two 
feet,  and  presenting  even  in  short  distances  all  the  gradations  from 
a  black  shale  to  coal  of  an  excellent  quality.  It  constitutes,  how- 
ever, a  constant  horizon,  notwithstanding  at  certain  localities  it 
becomes  so  attenuated  as  scarcely  to  retain  its  identity.  In  the 
middle  and  lower  portions  of  this  group  local  developments  of  dark 
shales,  sometimes  more  or  less  carbonaceous,  are  not  unfrequent, 
beside  there  are  bands  of  impure  fossiliferous  limestone,  and  the 
lower  half  is  made  up  of  clays  and  arenaceous  beds.  The  lower 


176  REPORT  OF  STATE  GEOLOGIST. 

group  is  limited  above  by  several  layers  of  argillaceous  lime  rock, 
five  to  ten  feet  below  which  coal  A,  occurs,  varying  from  three  to 
fifteen  inches  in  thickness,  overlaid  by  black  shale  and  a  band  of 
compact  argillaceous  rock.  This  latter  horizon  is  subject  to  the 
most  remarkable  variations  of  any  of  the  beds  previously  described. 
Sometimes  the  black  shales  have  a  most  exagerated  development,  and 
then,  again, .  the  layer  of  earthy  rock  is  reduced  to  a  lenticular 
nodular  band,  or  lost  entirely.  The  base  of  this  group  rests 
immediately  upon  the  sandstone  overlying  the  Des  Moines  coal, 
which  is  regarded  as  the  upper  bed  of  the  lower  coal  -measures. 

The  coal  which  is  being  so  extensively  mined  in  the  vicinity  of 
the  city  of  Des  Moines,  presents  the  interesting  feature  of  three 
distinct  layers  of  coal  separated  by  thin  seams  of  clay,  so  that  the 
whole  are  wrought  as  one  bed,  the  maximum  thickness  of  which  is 
about  five  feet.  But,  independently,  the  layers  are  very  variable  in 
thickness  —  sometimes  the  upper  ones  are  the  most  important,  then 
again  the  lower  ones  become  the  best  developed,  as  may  be  seen  by 
examining  the  out  -  crops  upon  either  side  of  the  Des  Moines,  in  the 
upper  part  of  the  city.  The  middle  stratum,  however,  is  more  con- 
stant in  this  respect,  averaging  about  eighteen  inches  in  thickness, 
while  the  upper  and  lower  ones  range  from  six  to  thirty  inches. 
Overlying  the  Des  Moines  coal,  which  is  practically  but  one  bed, 
we  find  about  ten  feet  of  clay,  capped  by  eight  to  twelve  feet,  or 
more  of  soft  sandstone,  which  in  turn  is  overlaid  by  variegated  clays, 
exhibiting  a  vertical  section  of  the  strata  associated  with  this  coal 
horizon  of  about  forty  feet.  The  line  of  outcrop  of  the  coal  is 
probably  fifteen  to  twenty  feet  above  the  level  of  the  river,  and 
could  not  be  more  accessible  for  advantagous  mining.  Its  product 
has  received  the  local  name  of  "Diamond  coal,"  and  in  quality  it  is 
esteemed  the  best  coal  in  this  market.  The  importance  of  this  coal 
to  the  manufacturing  interests  of  Des  Moines  can  not  be  overesti- 
mated. 

Now,  that  we  have  made  ourselves  somewhat  familiar  with  the 
characters  associated  with  the  Des  Moines  coal  on  the  Des  Moines 
river,  let  us  at  once  transfer  our  examinations  to  the  Raccoon  river 
coal-field  proper,  immediately  to  the  westward.  Taking  the  road 
which  passes  along  the  north  side  of  the  valley  of  the  Raccoon, 


REPORT  OF  STATE  GEOLOGIST. 

three  miles  above  Des  Moines,  at  Pagan's  Mill,  in  the  bluff  on  Wal- 
nut creek,  at  an  elevation  of  about  sixty  feet  above  the  stream,  there 
are  indications  of  a  thin  stratum  of  coal,  overlaid  by  black  shales 
and  a  layer  of  clayey  limestone,  and  in  the  slope  above,  clays  and 
fragments  of  impure,  thin -bedded  limestone,  affording  us  our  first 
section  in  the  middle  coal-measures.  The  exposure  represents  the 
upper  portion  of  the  lower  group,  including  coal  A.  This  bed  has 
been  prospected  by  drifting  into  the  bank,  but  we  presume  it  was 
found  too  thin  for  profitable  working,  as  the  entry  is  now  in 
ruins,  and  appears  to  have  been  abandoned  for  some  time. 

The  fact  that  the  coal  at  Fagan's  mill  holds,  apparently,  a  position 
forty  feet  above  the  Des  Moines  coal,  very  naturally  would  seem  to 
offer  conclusive  evidence  that  this  bed  overlies  the  latter  by  as  many 
feet  as  constitute  the  difference  in  their  respective  levels  above  the 
level  of  the  Des  Moines  river.  It  is  not  thus,  however,  the  geologist 
arrives  at  his  conclusions  regarding  the  order  of  superposition  of 
strata ;  else  discrepancies  would  constantly  embarrass  the  observer, 
and  errors  without  number  would  unavoidably  accumulate  in  the  end, 
compelling  all  mining  enterprises  to  resort  wholly  to  the  expensive 
and  uncertain  expedient  of  practically  demonstrating  the  existence  of 
mineral  wealth,  which  experience  proves  has  oftener  than  otherwise 
resulted  in  the  irrecoverable  expenditure  of  millions.  Therefore  if 
we  would  master  the  details  of  structural  geology,  thereby  rendering 
our  science  subservient  to  the  interests  of  man,  we  must  apply  our- 
selves diligently  to  the  study  of  all  the  various  strata,  both  their 
lithological  and  external  peculiarities,  and  the  organisms  they  contain, 
which  latter,  though  they  may  range  through  a  greater  or  less 
thickness  of  strata,  always  give  us  reliable  data  in  the  manner  of 
their  association  in  the  various  horizons,  which  will  render  invaluable 
aid  in  our  examinations,  as  I  shall  presently  endeavor  to  show. 

Four  or  five  miles  above  Fagan's  mill,  in  the  bluff  banks  and 
ravines  upon  the  north  side  of  the  Raccoon,  in  the  vicinity  of  Fitzsim- 
mon's  mills,  several  layers  of  impure  limestone  are  quarried  for 
building  stone,  which  give  a  tolerable  exposure  at  an  elevation  of 
twenty  feet  above  the  stream.  A  quarter  of  a  mile  or  less  above, 
however,  just  below  the  mills,  the  same  beds  out  -  crop  in  the  river 

bank  ten  to  fifteen  feet  below  their  level  at  the  quarries.     By  the 
23 


178  KEPORT  OF  STATE  GEOLOGIST. 

association  of  fossils  found  in  these  thin  layers  of  argillaceous  lime- 
stone, we  at  once  recognize  them  as  belonging  to  the  horizon 
observed  at  Fagan's  mill,  though  then  shown  only  by  a  few  fragments 
out-cropping  here  and  there  a  few  feet  above  the  thin  coal  A.  By 
making  a  liberal  estimate  of  the  fall  of  the  river  between  the  two 
above  -  named  localities,  the  beds  at  Fitzsimmons7  are  found  to  occupy 
a  much  lower  level  by,  probably,  not  less  than  thirty  feet,  showing  that 
the  beds  gently  incline  as  we  ascend  the  valley  to  the  westward  from 
Des  Moines,  which  has  carried  coal  A  below  the  river  bed  at  Fitz- 
simmons'. The  inclination  of  the  strata  is  so  gradual,  and  the  beds 
are  so  subject  to  local  inequalities  and  undulations,  that  it  would  be 
extremely  difficult,  to  say  the  least,  to  make  any  trustworthy  observa- 
tions on  the  general  dip  of  these  beds  at  any  one  exposure.  This  is 
true,  too,  of  nearly  all  the  exposures  in  this  region ;  so  that  the 
impracticability,  the  absurdity,  of  recognizing  equivalent  horizons  at 
remote  localities  by  comparing  their  positions  in  reference  to  a 
common  base  of  level,  will  be  apparent  from  the  illustration  afforded 
by  the  localities  already  mentioned. 

The  next  considerable  exposures  ascending  the  river  are  found  in 
the  vicinity  of  the  Boone  estate,  and  a  couple  of  miles  above  in  the 
bluffs  upon  the  right  side"  of  the  valley  (sections  twenty  -  six  and 
twenty  -  seven,  township  seventy  -  eight,  range  twenty -seven,  Dallas 
county),  near  Mr.  Benjamin  Colton's,  to  whom  I  am  indebted  for  my 
knowledge  of  this  locality.  The  strata  at  this  point  outcrops  in  the 
sides  of  deep,  narrow  ravines,  and  though  the  exposures  are  limited 
and  isolated,  they  exhibit  when  brought  together  nearly  seventy  feet 
thickness  of  strata,  all  of  which  pertain  to  horizons  higher  in  the 
series  than  those  heretofore  mentioned,  or  to  the  middle  groups  of 
the  middle  coal.  Sixty  to  seventy  feet  above  the  river,  coal  B  is  met 
with,  resting  upon  clays,  and  overlaid  by  sandy  days  and  a  five  -  foot 
bed  of  sandstone,  embedding  large  trunks  of  ancient  club -mosses  ; 
and  above  the  sandstone  the  lower  black  shales  of  the  upper  group, 
capped  by  a  foot  layer  of  impure  limerock  charged  with  fossils,  com- 
pletes the  top  of  the  section.  Thirty  feet  below  coal  B,  layers  of 
compact  argillaceous  rock,  interbedded  with  dark  shales  and  varie- 
gated clays,  are  seen;  but  in  a  thickness  of  seventy  feet  only  the  one 
little  six  -  inch  bed  of  coal  occurs. 


REPORT  OF  STATE  GEOLOGIST.  ]_  79 

Four  miles  nearly  due  north  from  the  above  locality,  on  the  head- 
waters of  Sugar  creek,  near  Mr.  Huston's  place,  coal  B  outcrops  in 
the  margin  of  the  stream,  presenting  the  same  association  of  beds 
as  noted  in  the  section  near  Colton's.  Here,  however,  the  black 
shales  at  the  base  of  the  upper  group  have  a  much  greater  develop- 
ment than  at  the  former  locality,  and  the  bed  is  finely  exposed  all 
along  the  creek  for  half  a  mile  or  more  above,  when  it  disappears 
beneath  the  bed  of  the  stream  at  the  quarry  on  Mr.  Frank  Graham's 
farm  (section  six,  township  seventy- eight,  range  twenty  -  six,  Dallas 
county).  The  same  coal  -  bed  also  appears  on  a  branch  of  Walnut 
creek  near  Mr.  John  Cutler's  place,  four  or  five  miles  north  of  Hus- 
ton's. 

Regaining  the  valley,  three  miles  above  the  confluence  of  the 
North  Raccoon  at  Vanmeter's  Mills  on  the  South  Raccoon,  the  bluffs 
on  the  left  bank  give  a  very  perfect  exposure  of  the  upper  half  of 
the  middle  group.  Coal  B,  a  thin  band  of  rotten  coal  three  to  six 
inches  thick,  is  seen  in  the  face  of  the  bluffs  twenty  -  five  feet  above 
the  river,  and  overlaid  by  the  upper  sandstone  of  this  group.  Below 
the  coal,  clays  and  layers  of  argillaceous  rocks  alternate  to  the  water 
level.  The  lower  black  shale  of  the  upper  group  does  not  appear 
in  the  section  at  Vanmeter's,  but  in  the  bed  of  a  little  branch  on  Mr. 
Miller's  place,  and  at  the  crossing  of  the  Winterset  road  on  the 
Bulger,  two  miles  south  of  the  mills,  the  uppermost  layers  of  the 
sandstone  appear  in  the  bed  of  the  stream,  supporting  a  few  feet  of 
clays,  upon  which  rests  the  black  shales  and  bands  of  clayey  lime- 
stone, presenting  a  section  identical  with  that  at  Colton's,  five  miles 
below.  It  will  further  be  observed  that  the  position  of  coal  B,  at 
this  locality  would  still  indicate  a  slight  westerly  inclination  of  the 
strata. 

Again  let  us  make  a  detour,  and  ascend  the  valley  of  the  Bulger 
to  the  southwestward.  This  little  valley  has  been  selected  for  the 
route  of  the  C.,  R.  I.  &  P.  Railroad,  in  its  ascent  from  the  Raccoon 
Valley  to  the  "  Quaker  Divide,"  and  consequently  its  importance 
as  a  great  commercial  thoroughfare  far  exceeds  that  of  the  larger 
streams  of  which  it  is  but  one  of  many  diminutive  affluents.  Near 
the  head  waters  of  the  Bulger,  and  just  within  the  borders  of  Madi- 
son county,  limestone  ledges  are  met  with,  which  doubtless  belong 


REPORT  OF  STATE  GEOLOGIST. 

to  the  upper  coal-measures,  and  are  high  above  any  rock  exposures 
we  shall  see  on  the  Raccoon  rivers.  These  ledges  afford  a  very  excel- 
lent, durable  building  stone,  and  when  the  railroad  shall  have  been 
completed  to  these  quarries,  their  value  will  be  greatly  enhanced. 
There  are  also  thin  beds  of  carbonaceous  shale  in  the  upper  coal- 
measures,  as  shown  by  Dr.  White  ;  and  on  the  head -waters  of  Bear 
creek,  on  the  southern  line  of  Dallas  county,  in  the  vicinity  of  Mr. 
Price's,  one  of  these  black  shale  horizons  of  the  upper  coal-measures 
is  found  underlying  limestones,  very  similar  if  not  indentical  with 
those  on  the  upper  course  of  the  Bulger.  The  elevation  of  these 
quarries  above  the  South  Raccoon  at  Yanmeter's  can  not  be  far  from 
two  hundred  feet;  and  when  we  t,.ke  into  consideration  the  inclina- 
tion of  the  middle  coal  strata  in  the  same  direction,  we  may  safely 
estimate  their  elevation  above  coal  B  at  one  hundred  to  one  hundred 
and  fifty  feet. 

From  Bear  creek  we  strike  across  the  beautiful  upland  prairie, 
known  as  the  ''Quaker  Divide,"  to  the  northward,  and  gain  the  hights 
overlooking  the  valleys  of  the  South  and  Middle  Raccoon  rivers 
in  the  vicinity  of  their  confluence.  The  south  side  of  the  valley  is 
bounded  by  steep,  wooded  bluffs,  and  a  low  sandstone  ridge  crowned 
with  forests  rises  between  the  two  streams.  The  north  side  of 
the  valley  rises,  terrace  upon  terrace,  to  the  general  upland  level, 
and  dotted  in  every  direction  with  thrifty  farms.  Upon  one  of  these 
high  benches,  on  the  east  bank  of  the  Middle  Raccoon,  the  prosper- 
ous manufacturing  village  of  Redfield  is  located. 

Descending  into  the  valley,  the  first  exposures  we  meet  with  in  the 
river  bank,  just  below  the  Newport  Woolen  Mills,  presents  arena- 
ceous beds  crowded  with  lenticular  concretions,  which  strongly  recall 
the  deposits  underlying  the  coal  at  Des  Moines.  Ascending  thence 
the  Middle  Raccoon,  a  short  distance  above  its  mouth,  in  the  left 
bank  (section  nine,  township  seventy-eight,  range  twenty-nine,  Dallas 
county)  on  lands  belonging  to  J.  Ward  Redfield,  Esq.,  a  bed  of 
coal  outcrops,  overlaid  by  clays  and  a  heavy  -  bedded  sandstone, 
thirty  to  fifty  feet  thick,  presenting  a  section  of  strata  essentially 
like  that  described  at  Des  Moines.  The  Redfield  coal,  like  the  Des 
Moines  bed,  is  not  a  single  bed,  but  consists  of  two  layers  separated 
by  a  thin  clay  parting.  It  differs,  however,  from  the  Des  Moines 


REPORT  OF  STATE  GEOLOGIST. 

bed,  in  being  one  layer  less,  although  it  still  retains  an  aggregate 
thickness  of  three  feet.  With  these  facts  alone  we  could  hardly 
prove  beyond  a  doubt  the  identity  of  these  banks.  It  is  well  known 
that  coal-beds  are  very  variable  in  their  physical  characters,  and 
not  unfrequently  the  lithological  characters  of  the  associated  strata 
become  changed  to  such  a  degree  as  to  be  almost  or  quite  unrecogni- 
zable at  distant  localities.  However,  in  this  instance,  we  are  not  left 
in  doubt  regarding  the  validity  of  the  identification  ;  and  notwith- 
standing the  exaggerated  enlargement  of  sandstone  above  the  coal 
at  Redfield,  we  shall  be  able  to  show  conclusively  that  the  Des  Moines 
and  Redfield  coals  belong  to  one  and  the  same  horizon. 

If  we  take  the  valley  road  leading  from  Redfield  to  Pariora,  we 
will  meet  with  exposures  of  the  sandstone,  which  overlies  the  Red- 
field  coal,  at  frequent  intervals  in  the  bluffs  between  Redfield  and  the 
Musquito.  A  short  distance  above  the  Musquito  creek  bridge,  in  the 
bluffs  on  the  east  side  of  the  creek,  at  Parker's  bank,  coal  A  of  the 
middle  series  outcrops  at  an  elevation  of  thirty  feet  above  the  level  of 
the  Middle  Raccoon.  The  coal  is  six  inches  thick,  and  is  overlaid  by 
the  black  shales,  band  of  argillaceous  lime  -  rock  and  clays  usually 
associated  with  this  bed.  At  Piatt's  bank,  a  few  hundred  yards 
above,  the  black  shales  have  increased  in  thickness  from  eighteen 
inches  to  forty  inches ;  the  "  cap  -  rock  "  only  exists  as  thin  pyritif- 
erous  modules,  above  which  brown,  yellowish  and  grey  shales  occur, 
which  are  in  places  charged  with  fossils.  The  coal  is  about  the  same 
thickness  at  both  banks,  but  in  other  respects  they  could  hardly  be 
more  dissimilar.  About  a  quarter  of  a  mile  southwesterly  from  Par- 
ker's bank,  a  ledge  of  rocks  juts  into  the  Middle  Raccoon,  which  upon 
examination  proved  to  be  the  upper  argillaceous  layers  of  the  lower 
group  of  the  middle  series,  and  present  almost  the  same  characters 
they  possess  at  Fitzsimmons',  eighteen  miles  east.  Although  these 
beds  are  not  seen  at  Parker's  and  Piatt's  banks,  having  been  removed 
by  denudation,  they  nevertheless  overlie  that  coal  -  bed,  and  their 
occurrence  in  the  river  margin,  thirty  feet  below  the  level  of  the  coal 
at  Parker's,  indicates  a  southwesterly  inclination  of  the  beds  equiva- 
lent to  about  one  hundred  feet  to  the  mile  at  this  locality.  Presently, 
however,  we  shall  see  the  sequence  of  these  beds  fully  exemplified, 
and  also  their  relation  to  the  coal  at  Redfield. 


182  REPORT  OF  STATE  GEOLOGIST. 

Crossing  the  South  Raccoon  a  short  distance  above  the  confluence 
of  the  Middle  Raccoon  we  ascend  by  a  steep  acclivity  to  the  uplands 
upon  the  south  side  of  the  valley.  The  road  passes  over  a  natural, 
though  somewhat  obscure,  exposure  composed  of  layers  of  impure 
limestone,  identical  with  those  last  observed  in  the  banks  of  the 
Middle  Raccoon  near  Mr.  Fee's.  This  band,  clays  and  fragments 
of  hard,  earthy  lime-  rock  are  seen,  and  a  faint  trace  of  a  carbon- 
aceous band  indicates  the  horizon  of  coal  A,  at  a  level  of  sixty  -  five 
to  seventy -five  feet  above  the  coal  at  Redfield,  a  mile  to  the  north- 
east. Continuing  up  the  valley  of  the  South  Raccoon  two  miles 
above  the  last-named  locality,  on  the  borders  of  Dallas  and  Guthrie 
counties,  one  of  the  most  interesting  and  important  exposures  in  the 
valley  was  examined.  The  discovery  of  this  locality  I  owe  to  Mr. 
Peter  Marshall,  who  by  intelligently  -  directed  practical  examinations 
had  already  made  himself  perfectly  familiar  with  the  local  geology, 
and  to  the  writer  it  is  a  particular  pleasure  here  to  acknowledge  the 
valuable  co  -  operation  he  gave  me  in  ray  field  -  examinations,  and  the 
kindness  he  showed  to  the  members  of  my  party  during  our  stay  in 
this  vicinity.  At  this  locality,  which  we  shall  call  the  "  Marshall 
section,"  the  strata  have  a  very  decided  westerly  dip.  At  the  lower 
end  of  the  bluff,  a  six  -inch  bed  of  coal  outcrops  at  the  water-level, 
and  which  is  overlaid  by  a  bed  of  black  shales  and  impure  limestone, 
five  to  eight  feet  of  clay,  and  four  feet  of  earthy  lime  -  rock  with 
clayey  partings,  upon  which  thirty  feet  or  more  of  clays,  sandy  shales 
and  thin  beds  of  sandstone  are  superimposed,  affording  a  complete 
section  of  forty  -  five  feet,  the  lower  part  of  which  presents  a  typical 
exposure  of  coal  A  and  the  beds  forming  the  top  of  the  lower  group 
of  the  middle  coal  -  series.  No  other  locality,  to  my  knowledge,  ex- 
hibits so  satisfactorily  at  a  single  exposure  the  direct  order  of  super- 
position of  the  members  which  form  the  upper  part  of  the  lower 
group  and  the  base  of  the  middle  group  of  this  series.  Five  hundred 
yards  below  the  "Marshall  section,"  coal  A  outcrops  in  the  hill -side 
forty  feet  above  the  level  it  occupies  at  the  latter  exposure.  The 
easterly  -  rising  of  the  strata  at  this  locality  corresponds  precisely 
with  \vhat  was  observed  in  connection  with  the  same  horizons  on 
Musquito  creek,  four  miles  northward.  The  forces  which  upraised 
the  Des  Moines  coal  above  the  level  of  the  Middle  ^Raccoon  at 


REPORT  OF  STATE  GEOLOGIST.  183 

Re>lfield,  also  uplifted  the  superincumbent  strata  of  the  middle  series, 
giving  rise  to  a  broadly  -  arched  anticlinal  ridge,  upon  whose  flanks 
the  strata  sweep  down  in  opposite  directions,  and  gradually  accumu- 
late vertically,  bed  upon  bed,  as  they  approach  the  axis  of  the  shallow 
synclinal  depression  which  occupies  the  intervening  country  between 
the  Des  Moines  and  the  mouth  of  the  Middle  Raccoon,  a  distance 
of  thirty  miles.  Hence,  we  shall  at  once  understand  the  occurrence 
of  beds  pertaining  to  the  middle  and  upper  groups  of  the  middle 
coal,  as  at  Vanmeter's,  at  the  same  levels  occupied  by  much  lower 
strata  whose  edges  are  exposed  high  upon  the  flunks  of  the  two 
parallel  anticlinal  ridges  which  define  the  east  and  west  margins  of 
the  intervening  depression. 

Nearly  three  miles  west  of  the  Marshall  section,  at  Miller's  coal- 
bank,  a  six  to  ten  inch  coal  -  bed  has  been  opened,  which  is  equiva- 
lent to  the  black  shale  horizon  at  the  base  of  the  upper  group  of  the 
middle  series.  It  is  very  seldom  that  coal  is  found  with  this  bed,  and 
its  occurrence  at  this  locality  affords  an  interesting  illustration  of  the 
local  deposition  of  a  thin  layer  of  coal  at  the  bottom  of  a  well- 
characterized  and  constant  horizon  of  carbonaceous  shales.  Coal  B, 
and  the  overlying  sandstone  are  not  exposed  at  Miller's  bank;  but 
in  the  banks  of  the  South  Raccoon,  south  of  Morrisburg,  the  sand- 
stone and  carbonaceous  horizon  above  were  observed,  and  in  a  boring 
half  a  mile  above,  a  bed  of  coal  is  said  to  have  been  found,  which  may 
be  equivalent  to  coal  B. 

Four  miles  south  of  Morrisburg,  on  Deer  creek  (section  twenty, 
township  seventy  -  eight,  range  thirty,  Guthrie  county)  at  Lonsdale's 
bank,  a  two  -  foot  bed  of  coal  outcrops,  and  is  overlaid  by  three  to 
four  feet  of  dark,  highly  -  fossiliferous  shales.  Ten  feet  above  the 
coal  a  soft,  yellow  sandrock  is  imperfectly  exposed,  between  which 
and  the  dark  shales  a  second  band  of  impure  coal  is  said  to  occur. 
In  the  slope  forty  -  five  feet  above  the  coal,  layers  of  compact  grey 
limestone  are  seen,  which  is  the  highest  rock  exposed  at  this  locality. 
The  coal  at  this  locality  is  regarded  as  the  uppermost  coal  -  bed  of 
the  middle  -  series,  or  coal  C.  It  is  one  of  the  conspicuous  palaeoh- 
tological  horizons  in  the  coal  -  measures  ;  containing  an  assemblage 
of  minute  fossil  -  forms,  which  readily  distinguish  this  from  all  other 
carbonaceous  horizons  of  the  middle  coal-measures.  The  present 


REPORT  OF  STATE  GEOLOGIST. 

workings  at  this  locality  are  on  lands  belonging  to  Mr.  John  Lons- 
dale  of  Dale  City.  The  coal  varies  in  thickness  from  twenty  to  thirty 
inches.  Its  elevation  above  the  creek  greatly  facilitates  the  working 
of  the  bank.  The  coal  is  excellent  in  quality,  and  with  the  rapid 
settlement  of  the  beautiful  country  about,  it  will  prove  an  important 
source  of  wealth  to  that  section. 

Four  miles  west  of  Dale  City,  on  Spring  Branch  of  Beaver  creek, 
near  Mr.  Loring  Mann's,  horizons  equivalent  to  coal  B  and  the  lower 
carbonaceous  horizon  of  the  upper  group  are  found;  but  neither  of 
the  carbonaceous  horizons  are  here  coal -bearing.  However,  higher 
up  the  Beaver,  two  miles  northwestward  from  Spring  Branch  (in 
lot  4,  section  5,  township  78,  range  8,  Guthrie  county,)  the  same 
beds  appear,  presenting  a  marked  contrast  to  their  appearance 
on  Spring  Branch.  Coal  B  here  affords  a  twelve  -inch  bed  of  coal; 
and  twelve  to  fifteen  feet  above,  the  lower  black  shales  of  the  upper 
group  are  underlaid  by  a  four -inch  layer  of  coal,  presenting  pre- 
cisely the  same  appearance  possessed  by  this  bed  at  Miller's  bank. 
Mr.  Thos.  Coleman  informed  us  of  other  localities  in  this  neighbor- 
hood where  the  same  bed  has  been  seen,  and  it  is  not  improbable 
that  coal  B  may  be  found  much  thicker  in  this  vicinity.  Indeed,  at 
Marshall's  coal  bank,  on  Long  Branch  in  the  southeast  corner  of 
Guthrie  county,  a  very  good  bed  of  coal  one  to  two  feet  thick  is 
being  mined,  and  which,  I  am  inclined  to  believe,  belongs  to  this 
horizon. 

Thus  far  our  examinations  have  been  confined  to  the  valleys  of 
the  Raccoon  and  South  Raccoon  rivers,  along  a  nearly  direct  line 
extending  west  from  Des  Moines  forty -five  miles  into  the  interior. 
We  have  had  opportunity  to  study  all  the  members  of  the  middle 
coal -series,  from  the  Des  Moines  coal  of  the  lower  coal-measures 
to  the  arenaceous  deposits  and  limestones  at  the  base  of  the  upper 
coal-  series.  And  it  now  remains  only  to  describe  the  principal  coal- 
exposures  found  along  the  Middle  and  North  Raccoon  rivers,  both  of 
which  streams  have  afforded  excellent  facilities  in  the  prosecution 
of  the  investigations  of  this  division  of  our  coal  -  measures. 

At  frequent  intervals  along  the  Middle  Raccoon  between  Mr.  Fee's 
and  Huggin's  branch  two  miles  above,  rock  -  exposures  appear  in  the 
bluffs,  and  as  we  ascend  the  stream  the  westerly  inclination  of  the 


REPORT  OF  STATE  GEOLOGIST. 

strata  brings  successively  to  view  higher  and  higher  beds,  comprising 
the  arenaceous  and  argillaceous  bulk  of  the  lower  half  of  the  middle 
grouD  of  the  middle  series ;  and,  finally,  in  the  high  bluff  opposite  the 
mouth  of  Huggin's  branch,  the  remainder  of  this  group  may  be  seen, 
crowned  by  the  bed  of  sandstone.  A  few  feet  below  the  sandstone, 
coal  B  is  represented  by  a  six-  inch  band  of  impure  coal  at  an  eleva- 
tion of  about  one  hundred  feet  above  the  river.  Ascending  Huggin's 
branch  in  a  westerly  direction,  the  same  beds  are  again  observed,  but 
at  a  much  lower  level,  and  the  black  shale  at  the  base  of  the  upper 
group  here  makes  its  appearance.  Near  the  head  of  the  branch, 
about  a  mile  from  its  mouth,  at  Huggin's  bank,  a  characteristic  sec- 
tion of  the  Lonsdale  coal,  or  coal  C,  is  found,  (Section  2,  Township 
78,  Range  30,  Guthrie  county.)  The  coal  is  two  feet  thick,  and  is 
overlaid  by  the  dark  shale  which  presents  its  usual  varied  fauna. 

About  three  miles  above  Fee's,  at  Duck's  Mill,  a  fine  section  of 
strata  appears  in  the  bluffs  upon  either  side  of  the  Middle  Raccoon, 
exhibiting  in  detail  the  upper  portion  of  the  middle  group,  and  in 
the  tops  of  the  bluffs  northwest  of  the  mills,  coal  C  is  obscurely 
exposed.  The  lower  black  shale  of  the  upper  group  is  finely 
developed  at  this  locality,  but  no  coal  is  associated  with  it.  Ten  to 
fifteen  feet  below  this  shale  coal  B  occurs,  varying  from  four  to  ten 
inches  in  thickness,  as  may  be  seen  in  the  bluff  above  the  mills. 

In  the  vicinity  of  Tarn's  mills,  one  or  two  miles  above  Duck's 
mills,  numerous  exposures  are  met  with  in  the  main  identical  with 
those  just  discovered.  In  the  hillside  near  the  mills,  coal  B  outcrops 
at  an  elevation  of  forty  -  five  feet  above  the  river,  and  is  represented 
by  a  six  inch  lawyer  of  rotten  coal.  The  sandstone  overlying  the 
coal  is  well  developed,  being  some  ten  feet  thick.  Three  or  four  feet 
above  the  sandstone,  the  lower  black  shale  of  the  upper  group,  capped 
by  its  argillaceous  cap -rock,  is  also  well  shown.  But  no  signs  of 
the  presence  of  coal  C  were  detected  at  this  locality.  A  mile  north  of 
of  the  mills,  on  Hook's  branch  coal  B  affords  a  handsome  layer  of  coal 
eight  inches  thick.  Descending  this  picturesque  little  dell,  the 
argillaceous  limestone  layers  of  the  upper  part  of  the  middle 
group  are  successively  passed  over,  affording  a  plentiful  harvest  of 
fossils;  and  toward  its  entrance  the  arenaceous  beds  of  the  lower 
portion  of  the  group  are  met  with.  At  this  point  the  Middle  Raccoon 


186  REPORT  OF  STATE  GEOLOGIST. 

abruptly  bends  westward,  and  half  a  mile  above  the  branch,  on 
the  north  side  of  the  river,  a  high  bluff  gives  an  imperfect  section  of 
the  same  beds  above  described.  Ninety  feet  above  the  water  the 
black  shales  of  the  upper  group  appear  at  the  surface,  arid  eight  feet 
below  this  bed  the  sandstone  which  overlies  coal  B  outcrops.  The 
elevation  of  the  above  horizons  at  this  exposure,  compared  with 
their  level  above  the  river  at  the  mills,  shows  a  westerly  uprising  of 
the  strata  at  the  rate  of  about  thirty -five  feet  to  the  mile.  A  few 
hundred  yards  above  the  last  mentioned  exposure,  coal  A  has  been 
brought  to  view  above  the  water  level.  This  bed  is  six  to  ten  inches 
thick,  and  capped  by  a  massive  sheet  of  dark  calcareous,  fossiliferous 
shales  twenty  inches  thick,  above  which  twelve  to  fifteen  feet  of  blue 
clays  are  exposed.  The  whole  aspect  of  this  horizon  at  this  locality 
is  so  unlike  its  usual  condition,  that  we  would  be  at  a  loss  to 
determine  its  stratigraphical  position  under  less  fortunate  circum- 
stances. 

In  the  vicinity  of  Panora,  Guthrie  County,  the  lower  group  of  the 
middle  coal  is  well  exposed,  affording  at  several  localities  interesting 
sections  of  coal  A.  At  Brumbaugh's  Mill,  and  in  the  vicinity  of 
the  Panora  Woolen  Mills,  the  coal  is  ten  to  fourteen  inches  thick, 
and  of  good  quality.  The  cap -rock  here  is  more  regular  than  at 
many  localities,  and  gives  a  self-supporting  roof  to  the  entries, 
which  renders  the  working  of  the  coal  economical  and  remunerative. 
The  principal  banks  are  Knowlton's,  Frazier's,  Wilson's  and 
Wasson's.  At  the  latter  bank,  the  uppermost  layers  of  the  lower 
group  are  exposed  in  the  ravine  above  the  coal -bank,  and  in  the 
bottoms  near  at  hand  a  shaft  has  penetrated  the  underlying  clays 
and  sandstone,  to  the  depth  of  forty  feet  below  coal  A,  which  I 
hardly  think  has  yet  reached  the  heavy  deposit  of  sandstone  over- 
lying the  Redfield  coal  -  bed.  At  the  Panora  Mills  the  same 
horizons  are  exhibited,  but  here  presenting  some  striking  modifica- 
tions. The  elevation  of  the  coal  above  the  river  level  is  about  the 
same  at  all  the  localities  —  twenty  to  twenty  -  five  feet  —  which 
indicates  a  gentle  rise  of  the  strata  as  we  ascend  the  stream  north- 
westerly. Messrs.  Hanyan  and  Nichols,  at  the  latter  locality,  have 
caused  a  shaft  to  be  sunk  in  the  bed  of  the  river,  which  encountered 
the  same  beds  noted  in  the  shaft  at  Wasson's  bank,  a  mile  and  a  half 


REPORT  OF  STATE  GEOLOGIST. 

below.  Coal  A,  also  outcrops  in  a  ravine  near  Panora  Mills,  but  the 
coal  is  reduced  to  a  two  -  inch  seam.  Above  the  coal,  massive  beds 
of  sandstone  and  shales  occur,  which  are  seen  to  advantage  opposite 
the  mills.  Should  the  strata  continue  to  rise  as  we  ascend  the 
valley,  the  upper  beds  of  the  lower  coal  -  measures  would  be  brought 
to  the  surface  a  few  miles  above  Panora.  Indeed,  this  seems  to  be 
really  the  case. 

Some  miles  northwest  of  Panora,  at  Shaw's  bank,  a  coal  -  bed  has 
been  opened  in  the  river  bank  but  little  above  low  -  water  mark. 
The  entry  was  closed  with  rubbish,  precluding  any  actual  examina- 
tions, and  in  consequence  only  the  most  meagre  and  unsatisfactory 
data  were  gained  respecting  the  physical  characters  of  the  bed  and 
its  stratigraphical  position.  Three  miles  above  Shaw's,  on  Spring 
run,  a  coal  -  bed  has  been  opened  on  lands  belonging  to  Mr.  John 
Clark.  The  bank,  however,  was  concealed  by  the  debris  from  the 
disintegrating  sandstone  which  immediately  overlies  the  coal.  Still 
higher  up  the  valley,  in  the  northern  part  of  Guthrie  County,  and 
in  Carroll  County,  sandstones  and  clays  are  seen  in  many  of  the 
bluffs,  which  frequently  give  exposures  of  an  hundred  feet  in  hight. 
Here  and  there,  thin,  interrupted  carbonaceous  bands  occur  in  the 
ferruginous  grits  and  clays,  and  thin  sheets  of  gravel  are  interstrati- 
fied  with  the  finer  materials. 

At  Mount's  coal -bank,  seven  miles  below  Raccoon  Rapids,  (sec- 
tion twenty  -  eight,  township  eighty  -  one,  range  thirty  -  two,  Guthrie 
County)  a  one -foot  bed  of  coal  has  been  opened,  overlaid  by  black, 
fossiliferous  shales,  and  light- colored  clays  with  concretionary  band 
at  top,  upon  which  rests  a  soft  sand  deposit.  And  three  miles  and 
a  half  above  (section  twenty -four,  township  eighty -one,  range 
thirty  -  three),  apparently  the  same  bed  shows  itself  in  the  right 
bank  of  the  Middle  Raccoon,  characterized  by  the  same  shales  and 
organisms  found  at  Mount's  bank.  There  are  other  coal -banks  in 
this  vicinity,  which  are  doubtless  referable  to  the  same  bed. 

On  Musquito  creek,  five  miles  east  of  Panora,  at  HowelPs  bank, 
coal  A  is  again  met  with,  affording  a  twelve  -  inch  bed,  and  agreeing 
in  all  essentials  with  the  banks  near  Panora,  although  the  bed  at  this 
locality  is  high  above  the  level  of  its  outcrop  on  the  Middle  Raccoon. 

The  North  Raccoon  river  passes  nearly  through  the  middle  of  Dallas 


]38  REPORT  OF  STATE  GEOLOGIST. 

county  in  a  northerly  and  southerly  course,  cutting  across  the  middle 
coal-measures  nearly  at  right  angles  to  the  northern  border  trend  of 
this  series.  Ascending  the  valley  from  its  confluence  with  the  South 
Raccoon,  the  strata  ascend  or  uprise  to  the  northward  at  a  much 
more  rapid  rate  than  the  fall  of  the  stream  in  the  opposite  direction; 
and  reaching  a  point  a  few  miles  north  of  Adel,  the  most  northerly 
exposures  of  the  lower  members  of  the  middle  coal  appear  in  the 
ravines  high  above  the  river.  Beyond  the  borders  of  the  middle 
series,  horizons  are  encountered  which  present  a  marked  contrast 
to  the  strata  found  along  the  lower  course  of  the  stream,  in  some 
respects  recalling  the  beds  on  the  Middle  Raccoon  above  Panora. 

One  or  two  miles  east  of  Adel,  on  Hickory  and  Miller's  branches, 
the  upper  beds  of  the  middle  group  are  finely  exhibited.  On  Hick- 
ory branch  the  upper  sandstone  of  the  middle  group  furnishes  a  very 
good  freestone,  which  is  extensively  quarried  for  building  purposes. 
Just  above  this  bed,  at  one  or  two  places,  the  same  black  shale  of 
the  upper  group  is  imperfectly  exposed ;  and-  four  feet  below  the 
sandstone  a  thin  carbonaceous  band  appears,  which  is  the  represen- 
tative of  coal  B.  In  the  section  on  Miller's  branch  the  same  beds 
are  displayed,  and  in  the  lower  portion  of  the  bluff  a  local  develop- 
ment of  black  shale  is  found,  but  which  is  not  a  reliable  horizon.  A 
short  distance  north  of  Adel,  on  Butler's  branch,  at  the  base  of  a 
low  bluff  composed  of  sandy  shales  and  sandstone,  a  twelve -inch 
bed  of  coal  is  said  to  occur. 

At  Chaney's  coal  -  bank,  four  miles  north  of  Adel,  coal  A  appears, 
which  is  here  twelve  inches  thick,  overlaid  by  the  clays  and  thin,fos- 
siliferous  limestone  layers  which  form  the  top  of  the  lower  group. 
Lower  down  the  ravine  a  still  lower  bed  of  coal  outcrops  in  the  banks 
of  the  stream,  which  probably  belongs  to  the  lower  coal  -  measures. 

North  of  Chaney's  the  middle  coal-measures  have  disappeared 
and,  although  exposures  of  clay  and  sandstone  are  not  unfrequent, 
no  coal  is  again  met  with,  to  my  knowledge,  before  reaching  the 
southern  border  of  Green  county.  On  Brown's  branch,  seven  miles 
below  Rippey,  Green  county,  a  ten  -  inch  bed  of  coal  makes  its 
appearance,  and  in  the  river  bank  near  the  mouth  of  the  branch, 
an  eighteen -inch  coal-bed  is  said  to  occur,  which,  however,  is 
only  exposed  at  low  water.  Two  and  a  half  miles  below  Rippey, 


REPORT  OF  STATE  GEOLOGIST. 

at  Bussy's  bank,  an  eighteen  -  inch  coal  -  bed  is  mined,  which  bears 
a  close  resemblance  to  the  upper  coal-bed  on  Polecat  creek,  near 
Boonsboro,  on  the  Des  Moines. 

The  northern  limits  of  the  middle  coal-measures  may  be  defined 
by  a  line  passing  through  the  middle  of  the  north  half  of  Guthrie 
and  Dallas  counties,  in  an  east -and- west  direction,  nearly  to  the 
Des  Moines  river,  thence  trending  southeast  through  Dallas,  Polk, 
and  into  Warren  county,  nearly  parallel  with  the  course  of  the  Des 
Moines,  as  far  as  it  has  been  traced.  To  the  north  of  this  line  the 
lower  coal  -  measures  appear  at  the  surface,  and  stretch  northward 
into  Green  and  Carroll  counties.  The  northern  boundary  of  the 
upper  coal-measures,  in  this  part  of  the  State,  is  parallel  with  that 
of  the  middle  series,  and  is  definitely  defined  by  the  divide  which 
separates  the  Raccoon  rivers  from  the  Three  River  district  to  the 
south.  Therefore,  the  middle  coal  -measures  occupy  a  belt  of  coun- 
try about  fifteen  miles  wide  and  extending  east  and  west  forty  -  five 
miles  or  more. 

It  has  been  demonstrated  that  the  middle  and  upper  coal  -  measures 
possess  no  thick  beds  of  coal.  Although  coal  occurs  in  these  upper 
measures,  the  beds  are  thin,  and  it  is  only  where  they  are  locally 
thickened,  as  at  Marshall's  bank  in  Guthrie,  that  they  present  good, 
workable  beds.  However,  the  upper  bed  of  the  middle  coal- 
measures  is  very  regular,  with  an  average  thickness  of  twenty  inches. 
Wherever  it  is  found  in  the  country  of  the  South  Raccoon,  it  can  be 
easily  mined,  and  is,  probably,  the  best  bed  in  the  two  upper  divisions 
of  the  coal-measures.  It  doubtless  can  be  reached  by  boring,  at 
many  places  to  the  southward  of  Lonsdale's  bank  in  Guthrie  county, 
but  to  the  east  and  north  and  westward  it  has  been  swept  away  by 
the  denuding  agencies  which  exposed  the  lower  groups  of  the  middle 
coal  -  measures,  and,  still  farther  to  the  northward,  revealed  the 
upper  portion  of  the  lower  coal  -  measures.  In  the  counties  imme- 
diately to  the  southward  of  Guthrie,  this  bed  is  buried  beneath  the 
limestones  and  shales  of  the  upper  coal  -  measures. 

The  lower  coal  -  measures  are  the  great  repository  of  mineral 
fuel,  and  to  this  series  we  must  look  for  the  main  supply  of  coal 
in  the  State.  Although  an  extensive  tract  of  country  bordering 
upon  the  Des  Moines  is  underlaid  by  the  lower  coal-measures,  the 


REPORT  OF  STATE  GEOLOGIST. 

the  general  southwesterly  inclination  of  the  strata,  in  connection 
with  the  ascent  of  the  surface  in  the  same  direction,  has  carried  this 
productive  series  beneath  the  middle  and  upper  coal  -  measures,  and, 
with  the  exception  of  the  Redfield  uplift,  they  are  wholly  lost  to 
view  in  the  southwestern  portion  of  the  State.  At  present  we  have 
no  reason  to  believe  that  the  lower  measures  are  any  less  productive 
in  their  southwestern  extension  than  they  are  along  the  Des  Moines. 
In  the  valley  of  the  Raccoon  and  on  the  lower  courses  of  the  South 
and  Middle  Raccoon  rivers,  the  horizon  of  the  Des  Moines  coal,  or 
upper  bed  of  the  lower  coal  -  measures,  may  be  reached  by  boring  at 
variable  depths,  depending  upon  the  stratigraphical  position  of  the 
locality  at  which  it  is  desired  to  seek  this  bed.  It  is  not  improbable 
that  below  Redfield  this  bed  may  be  found  above  the  level  of  the 
South  Raccoon,  or  within  a  limited  distance  beneath  the  surface  of 
the  valley.  But  to  the  eastward  it  gradually  sinks  deeper  and  deeper 
beneath  the  level  of  the  streams  until  reaching  the  mouth  of  Bulger 
creek,  at  which  point  it  probably  lies  at  a  depth  of  one  hundred  and 
fifty  feet,  or  thereabout,  below  the  river.  Between  the  Bulger  and 
the  Des  Moines,  the  strata  slowly  rise  eastward,  which  possibly  brings 
this  coal  horizon  within  sixty  to  eighty  feet  of  the  level  of  the  Rac- 
coon river  at  the  mouth  of  Sugar  creek.  And  ten  miles  in  a  direct 
course  east  of  Sugar  creek  this  bed  gains  the  surface  in  the  banks 
of  the  Des  Moines  river  at  the  city  of  Des  Moines.  But  it  must  be 
borne  in  mind  that  all  beds  of  coal  are  more  or  less  variable  in 
thickness,  particularly  if  they  extend  over  large  areas;  therefore,  the 
above  estimates  indicate  the  horizon  of  the  coal  rather  than  the 
actually  known  presence  of  the  fully-  developed  bed.  It  is  known 
that  below  the  Des  Moines  coal  all  the  heaviest  beds  of  the  lower 
coal  -  measures  are  found.  Dr.  White  has  described  many  of  these 
coal -banks,  and  they  compare  favorably  in  all  respects  with  the  coal 
of  corresponding  horizons  of  other  States. 


SURFACE 

GEOLOGY  OF  THE  MIDDLE  REGION  OF  WESTERN  IOWA, 


The  country  embraced  in  the  three  central  tiers  of  counties  lying 
between  the  Missouri  and  Des  Moines  rivers,  possesses  natural 
features  generally  common  to  the  western  half  of  the  State.  How- 
ever, on  a  more  careful  examination  of  the  ground,  both  with  refer- 
ence to  the  elimination  of  its  topographical  as  well  as  its  geological 
features,  we  find  certain  peculiarities,  on  the  one  hand,  common  to 
both  the  northern  and  southern  portions  of  this  region,  which,  when 
viewed  at  the  extreme  opposite  points  upon  the  east  and  west, 
present  little  in  common  with  one  another.  But  in  this  intermediate 
region  the  more  distinctive  surface  features  which  characterize  the 
extremes  give  way,  and  the  result  is  a  blending,  or  rather  a  toning 
down,  so  to  speak,  of  the  more  prominent  and  widely  diverse  topo- 
graphical features  which  are  no  where  to  be  found  more  beautifully 
displayed  than  in  Western  Iowa. 

The  streams  of  the  western  watershed  have  a  westerly  flow,  and 
seek  their  outlet  in  the  Missouri.  In  this  part  of  the  State  the  streams 
take  their  rise  in  the  great  plateau  which  separates  the  waters  of  the 
Mississippi  from  those  of  the  Missouri.  In  Shelby,  Audubon,  and 
the  southern  portions  of  Carroll  and  Crawford  counties,  several 
streams  take  their  rise,  which  flowing  southward,  reach  the  Missouri 
within  the  borders  of  the  State  of  Missouri.  Of  these  may  be  men- 
tionod  the  three  principal  branches  of  the  Nishnabotany  and 
Whitted's  creek,*  Musquito,  Keg  and  Cooper  creeks.  To  the  north- 
ward, the  Boyer,  Willow  and  Soldier  rise  in  Sac  and  Ida  counties, 

*  Whitted  creek  rises  in  Carroll  county,  and  flowing  southwesterly  falls  into  the 
West  Nishnabotany  a  few  miles  below  Harlan,  in  bhelby  county.  I  could  not 
learn  that  this  beautiful  little  stream  possessed  a  name,  and  hence  I  have  sug- 
gested the  above  name  in  honor  of  Mr.  P.  J.  WHITTED  of  Exira,  Audubon  county, 
who  was  one  of  the  first  surveyors  in  this  part  of  the  country,  and  whose  name 
has  been  thoroughly  identified  with  the  progress  and  best  interests  of  these  coun- 
ties from  their  earliest  settlement  to  the  present  time. 


192  REPORT  OF  STATE  GEOLOGIST. 

and  passing  diagonally  through  Crawford,  Harrison  and  Monona 
counties  reach  the  Missouri  along  the  middle  border  of  the  State. 
The  Little  Sioux  and  its  principal  tributaries,  the  West  Fork  and 
Maple  river,  head  in  the  northern  part  of  the  State,  and  drain  the 
fine  region  embraced  in  Ida,  Woodbury,  and  the  western  portion  of 
Monona  counties.  Along  their  upper  course  the  streams  become 
mere  drainage  depressions,  though  their  character  as  such  is  always 
distinctly  marked.  Upon  the  head-waters  of  the  numerous  small  rivers 
and  creeks  which  traverse  this  portion  of  the  western  watershed,  we 
do  not  find  the  streams  taking  their  rise  in  lakelets,  as  in  the  country 
east  of  the  grand  divide ;  on  the  contrary,  they  are  divided  into  a 
multitude  of  drainage  channels  which  mark  their  delicate  ramifica- 
tions to  the  very  crest  of  the  watershed  between  the  two  river 
systems,  and  by  this  means  a  system  of  the  most  complete  drainage 
is  effected.  These  upper  ramifications  have  been  called  "  draws," 
and  not  inappropriately,  as  their  beds  are  not  usually  occupied  by  a 
continuous  channel,  for  they  are  seldom  fed  by  springs;  but  their 
chief  use  is  to  collect  the  sarface  waters,  and  hence  it  is  only  during 
the  spring  and  autumn  seasons  that  their  beds  are  flooded.  In  the 
summer  their  waters  shrink  into  little  dark  pools,  and  their  beds  are 
carpeted  by  a  tall,  nutritious  herbage,  quite  in  contrast  to  the  lower 
grasses  of  the  surrounding  prairies.  These  streams  of  green  herbage 
follow  all  the  graceful  meanderings  of  the  channels  to  their  very 
sources,  and  impart  a  refreshing  feature  to  the  prairie  landscape. 

The  Kaccoon  river  system  is  tributary  to  the  DCS  Homes,  and  is 
the  most  considerable,  both  as  regards  the  size  of  the  streams  and 
the  area  which  they  drain,  that  occupies  the  country  between  the 
Des  Moines  and  the  grand-  divide  upon  the  east  slope.  The  courses 
of  the  four  principal  branches,  the  North,  Middle,  Bushy  Fork  and 
South  Raccoon,  are  nearly  at  right  angles  to  those  of  the  streams 
previously  mentioned  upon  the  western  watershed  and  parallel  with 
the  divide.  All,  with  the  exception  of  the  North  Raccoon,  take  their 
rise  in  Guthrie  and  Carroll  counties ;  while  the  latter  passes  through 
the  entire  length  of  Sac  county,  to  the  north,  and  heads  in  Buena 
Vista  and  Pocahontas  counties.  The  peculiarities  of  the  drainage 
upon  the  two  watersheds  are  widely  different ;  upon  the  western,  we 
meet  with  a  multitude  of  small  branches,  while  in  the  country  east 


REPORT  OF  STATE  GEOLOGIST.  193 

of  the  great  divide  the  larger  streams  possess  comparatively  few 
small  affluents.  Before  we  go  further,  let  us  make  a  brief  examina- 
tion of  the  deposits  in  which  the  varied  topographical  features  of  the 
region  are  moulded,  and  which  will  enable  us  the  better  to  under- 
stand the  origin  of  the  present  appearance  of  the  surface  in  this 
section  of  the  State.  The  superficial  deposits  which  occur  in  the 
western  part  of  the  State  are  the  drift  and  bluff.  In  the  country 
between  the  grand  divide  and  the  Des  Moines,  the  drift  is  largely 
developed,  consisting  of  blue  clays,  and  yellow,  sandy  clays,  which 
latter  is  usually  spread  over  the  greater  part  of  the  surface.  Upon 
the  west  slope  the  drift  rapidly  diminishes  in  thickness,  and  is  over- 
laid by  the  peculiar  yellow  clays  of  the  bluff.  This  latter  deposit 
reaches  its  greatest  development  on  the  western  borders  of  the 
State,  when  it  attains  a  somewhat  variable  thickness,  probably  at 
many  localities  not  less  than  two  hundred  feet.  The  fine  nature  of 
the  material  which  comprises  the  bluff,  seems  to  furnish  conclu- 
sive evidence  of  its  lacustrine  origin.  On  the  other  hand,  the 
coarse  materials  which  enter  so  largely  into  the  composition  of 
the  drift,  were  deposited  at  the  bottom  of  the  great  fresh  -  water  sea 
at  the  close  of  the  glacial  period.  The  bluff  clays  abut  upon  the 
Missouri  bottoms  in  ranges  of  steep  bluffs,  which,  when  visited  from 
the  valley,  or  looking  either  up  or  down  their  course  from  some 
eminence,  it  requires  but  little  effort  on  the  part  of  the  imagination 
to  transform  the  whole  landscape  into  one  of  lofty  mountain  ranges 
and  great  plain.  Although  in  the  region  of  the  drift  upon  the  east 
watershed  we  do  not  meet  with  such  bold,  exaggerated  surface  fea- 
tures ;  nevertheless,  that  section  possesses  its  strongly  marked  pecu- 
liarities, which  furnish  a  striking  contrast  to  the  country  bordering 
the  Missouri. 

Descending  the  water  -  courses  towards  their  confluence  with  the 
Missouri,  the  valleys  gradually  descend,  and  narrow  intervals  rise 
from  the  margins  of  the  streams  to  the  gentle  border  slopes  of  the 
uplands.  Along  their  lower  reaches,  the  streams  are  eroded  to  the 
depth  of  two  hundred  feet  and  upward,  and  their  exit  from  the 
uplands  is  guarded  by  the  massive  bights  of  the  great  lacustrine 
deposit.  Between  these  streams  the  surface  is  rolling,  though  sel- 
dom broken.  The  streams  themselves  are  bordered  by  steep,  grassy 


194  '          REPORT  OF  STATE  GEOLOGIST. 

banks,  and  their  beds,  with  few  exceptions,  are  filled  with  quicksands 
or  equally  treacherous  mire.  The  uplands  are  remarkably  free  from 
boggy  land,  and  "  sloughs  "  are  encountered  only  in  the  low  bottoms 
along  the  streams.  In  the  immediate  neighborhood  of  the  Missouri 
bottoms,  where  the  uplands  are  abruptly  terminated,  the  surface  is 
usually  broken,  and  the  bluffs  are  penetrated  by  deep,  narrow 
ravines,  shaded  by  dense  forest  growths,  whose  existence  one  little 
suspects  until  their  canon -like  beds  are  overlooked  from  the  ridges 
above.  The  Missouri  bottoms  form  one  of  the  most  remarkable 
peculiarities  of  the  West.  They  extend  the  entire  length  of  the 
State,  and  are  more  or  less  variable  in  width.  In  Harrison  County, 
between  the  Boyer  and  Little  Sioux,  the  bottoms  have  a  width  of 
eight  miles ;  and  in  Monona  and  Woodbury  Counties  they  crowd 
inland  a  distance  of  twelve  miles  or  more,  and  the  bluffs  which 
abruptly  define  the  eastern  margin,  do  not  again  approach  the  river 
until  within  a  few  miles  of  Sioux  City,  at  Floyd's  Bluff,  where  they 
form  a  conspicuous  headland  overlooking  the  turbid  waters  of  the 
Missouri  for  miles.  The  bottoms  rise  in  low  benches,  which,  in 
form,  have  all  the  characteristics  of  true  terraces,  although  they  are 
but  little  elevated  above  the  general  level.  These  benches,  however, 
are  composed  of  exceedingly  fine  materials,  and  in  this  respect  they 
differ  greatly  from  the  terraces,  or  "  second  bottoms,"  along  the 
streams  of  the  Mississippi  watershed.  Like  true  terraces,  they  are 
most  elevated  along  their  outer  margins,  and  slope  inland,  giving  rise 
to  the  little' lakes  and  channels  which  not  unfrequently  skirt  the  base 
of  the  bluffs  and  meander  through  the  bottoms,  -affording  a  natural 
drainage.  Throughout  the  entire  extent  of  the  bottoms,  the  soil  is 
of  unsurpassed  fertility,  and  the  day  is  not  distant  when  this 
immense  tract  of  alluvial  lands  will  hold  a  foremost  place  in  the 
agricultural  interests  of  the  West. 

As  has  been  previously  mentioned,  the  greatest  development  of 
the  bluff  deposit  occurs  in  the  Missouri  river  bluffs,  where  it  ranges 
from  one  hundred  to  two  hundred  feet  in  thickness.  To  the  north- 
ward, however,  the  deposit  gradually  diminishes  in  thickness,  and  in 
the  neighborhood  of  Sioux  City,  it  is  reduced  to  half  its  maximum  thick- 
ness in  the  counties  to  the  southward.  It  crowns  all  the  cretaceous 
hills,  and  gives  to  the  region  about,  that  peculiar  character  of 


REPORT  OF  STATE  GEOLOGIST. 

topography  pertaining  to  this  deposit.  Indeed  so  markedly  is  this 
manifest  that  the  presence  of  the  cretaceous  formation  can  hardly  be 
said  to  have  taken  more  than  an  insignificant  part  in  giving  the 
country  its  present  configuration. 

Underlying  the  bluff  material  along  the  Missouri  valley,  at  many 
localities,  we  find  a  thin  layer  of  sand,  with  pebbles  and  boulders, 
distinctly  arranged  in  layers  ;  and  which,  in  turn  is  underlaid  by  the 
clays  of  true  Drift  epoch.  But  more  frequently  the  thin  stratum  of 
modified  drift  material  is  found  resting  immediately  upon  the  rocky 
strata,  with  no  intervening  clays ;  and  sometimes  even  the  gravel  -  bed 
disappears,  and  the  base  of  the  bluff  comes  in  immediate  contact  with 
the  consolidated  rocks,  as  observed  in  the  environs  of  Sioux  City. 
However,  if  we  ascend  any  of  the  valleys  of  the  larger  inland  -  streams, 
as  the  Little  Sioux  and  the  Boyer,  as  we  recede  from  the  Missouri 
river  bluffs  eastward,  we  shall  very  soon  witness  a  gradual  increase 
in  the  development  of  the  gravel  -  beds ;  and  soon  low  outliers 
protruding  from  beneath  the  bluff  deposits,  will  add  an  unusual 
element  to  the  landscape,  and  however  inconspicuous  these  bunches 
may  be  they  are  always  sure  to  arrest  the  eye  and  gain  our  interest, 
if  no  other  than  this  very  obscurity.  On  the  Little  Sioux  the  gravel- 
beds  are  found  fifty  feet  above  the  stream,  overtopped  by  twice  that 
thickness  of  bluff.  And  at  Dennison,  at  the  confluence  of  the  two 
main  branches  of  the  Boyer,  similar  exposures  are  found,  from  which 
is  obtained  the  gravel  for  the  manufacture  of  the  concrete  brick  at 
that  place.  Also  near  Dennison,  on  Judge  Bassett's  farm,  certain 
layers  of  these  deposits  are  found  sufficiently  cemented,  to 
answer  for  laying  up  in  rough  walls.  Generally  speaking,  however, 
the  gravel  deposits  are  too  wasted  to  have  more  than  a  slight  influence 
.in  modifying  the  nature  of  the  soil,  which  is  still  decidedly  of  bluff 
origin. 

In  the  country  bordering  upon  the  Nishnabotanys,  the  bluff  pre- 
sents some  of  its  most  characteristic  features.  The  divides  are 
massive  and  rounded  in  outline,  and  descending  into  the  valleys  by 
those  long,  graceful  slopes,  it  is  not  unfrequently  difficult  to  draw 
the  demarkation  between  bottom  -  land  and  upland.  But  on  approach- 
ing the  grand  divide,  the  drift  is  frequently  found  high  in  the  slopes, 


196  REPORT  OF  STATE  GEOLOGIST. 

the  line  of  its  outcrops  studded  with  boulders,  and  giving  a  sort  of 
angularity  to  the  topography  which  is  wholly  foreign  to  the  bluff. 

Ascending  the  east  branch  of  the  Boyer,  the  bluff  clays  continue 
to  compose  the  great  bulk  of  the  uplands,  and  sweeping  over  the 
watershed  in  Carroll  and  Audubon  counties,  burying  deep  beneath 
its  mass  the  underlying  deposits,  it  forms  a  heavy  capping  upon  the 
divide  between  the  South  Raccoon  and  Brushy  Fork,  and  tips  the 
crest  of  the  ridge  between  the  latter  stream  and  Middle  Raccoon, 
upon  the  east  watershed.  At  this  point,  which  is  the  eastern  border  of 
the  bluff  in  this  section,  the  topography  assumes  a  totally  different 
aspect,  and  in.  many  respects  essentially  peculiar  to  that  section  of 
the  country  drained  by  the  Raccoon  rivers. 

But  to  return  to  the  west  watershed,  we  will  next  ascend  the  main 
branch  of  the  Boyer.  Starting  from  Denison,  our  route  thence  to 
the  northeast  corner  of  Crawford  county  traverses  the  beautiful  up- 
land upon  the  east  side  of  the  Boyer,  and  parallel  with  its  course. 
The  bluff-  clays  continue  to  impart  to  the  soil  and  to  the  surface- 
outline  of  the  country  its  well-marked  peculiarities  until  we  have 
passed  beyond  the  borders  of  Crawford  and  entered  Sac  county. 
Here  the  country  becomes  changed.  The  surface,  instead  of  pre- 
senting those  smooth,  graceful  slopes  and  finely  -  comminuted  soil 
everywhere  met  with  and  common  to  the  bluff  wherever  it  exists, 
stretches  to  the  northeastward  in  a  barely  perceptibly -rising  plain, 
traversed  by  long  files  of  low  wave  -  like  ridges  or  swells,  whose  crests 
are  paved  with  boulders  and  the  slopes  strewn  with  gravel.  We  have 
hardly  missed  the  presence  of  the  familiar  lacustrine  deposits  ere  we 
find  ourselves  environed  by  entirely  different  geological  and  topo- 
graphical phases.  We  are  again  standing  upon  the  great  divide, 
overlooking  almost  an  immensity  of  prairie,  the  horizon  to  the  east, 
west  and  south  presenting  a  continuity  as  unbroken  as  that  at  sea, 
but  which  to  the  northward  is  interrupted  by  the  heavy  drift -ridges 
whose  outlines  are  sharply  defined  against  the  background  of  deep- 
blue  sky  at  that  quarter.  Every  step  of  the  way  thence  to  Wall 
Lake  exhibits  the  uncovered  drift  deposits;  and  reaching  the  bluffs 
overlooking  the  North  Raccoon  at  Grant  City,  and  throughout  its 
course  below,  well  -  defined  terraces,  or  "  second  bottoms,"  border 


REPORT  OF  STATE  GEOLOGIST. 

either  margin  of  the  valley,  which  greatly  enhance  the  scenic  effect 
and  afford  beautiful  rural  situations. 

The  dividing  ridge  in  this  region  has  a  generally  northwest  and 
southeast  direction.  Between  Audubon  and  Guthrie,  and  in  Carroll 
county,  it  forms  a  sinuous  ridge,  from  the  crest  of  which  the  drain- 
age "  draws"  ,  descend  upon  either  slope,  on  the  one  hand  to  join 
the  numerous  affluents  of  the  Nishnabotany  and  the  Boyer,  and 
upon  the  other  to  augment  the  tributaries  of  the  Raccoon  rivers. 
But  as  we  pass  along  the  divide  to  the  northward,  in  the  northern 
portion  of  Carroll  county,  the  drainage  of  the  two  watersheds  is 
interlocked,  so  to  speak,  by  the  head -waters  of  the  Middle  Raccoon 
and  the  east  branch  of  the  Boyer  ;  and  here  the  divide  is  as  sharply 
defined  as  the  ridge  of  a  gable  roof.  Further  to  the  north  the  ridge 
expands  into  a  gently  undulating  plateau,  which  is  traversed  by  low 
ridges  of  drift,  producing  an  entirely  different  configuration  from 
what  it  possesses  to  the  southward.  These  ridges  are  composed  of 
the  loose  material  of  the  drift,  and  form  the  highest  land  in  this  part 
of  the  State,  with  an  elevation  above  the  level  of  the  sea,  probably, 
of  not  less  than  fifteen  hundred  feet.  The  broad,  shallow  depres- 
sion intervening  between  the  knobs  or  ridges  of  drift,  possess  a  rich, 
black,  gravelly  soil,  which  differs  in  many  respects,  excepting  in  fer- 
tility, from  the  soils  of  the  west  watersheds.  It  will  have  been  already 
seen  that  the  difference  in  the  soils  of  the  east  and  west  watersheds 
is  due  to  the  difference  in  the  nature  of  the  immediately  underlying 
deposits  in  the  two  sections.  Wherever  the  bluff  clays  are  found,  a 
fine,  light  -  colored,  durable  soil  is  produced,  which  is  particularly 
well  adapted  to  the  growing  of  cereals  ;  and  in  the  region  of  the 
drift,  east  of  the  dividing  ridge,  the  soil  is  of  a  loamy  nature,  though 
possessing  many  varieties,  susceptible  of  early  tillage,  and  returning 
abundant  harvests  to  thorough  cultivation. 

The  Raccoon  rivers  are  deeply  excavated  into  the  drift  and  coal- 
measures  ;  their  valleys  are  narrow  and  bordered  by  steep  bluff 
ascents,  and  usually  terraced.  But  along  that  part  of  the  courses 
of  the  South  Raccoon  and  Bushy  Fork  bordered  by  the  bluff  deposits,, 
either  these  "second  bottoms'7  are  wholly  obliterated  or  only  obscurely 
displayed  —  a  peculiarity,  as  heretofore  observed,  common  to  these 
deposits  wherever  they  are  found  associated.  The  moment,  however, 


198  REPORT  OF  STATE  GEOLOGIST. 

the  streams  pass  beyond  the  influence  of  the  bluff,  the  benches  which 
rise  step -like  upon  the  sides  of  their  valleys  assume  definite  out- 
lines, and  hence  continue  to  impart  to  the  valleys  a  prominent  and 
pleasing  feature  in  their  formation  and  appearance.  The  uplands 
are  level,  or  but  gently  undulating,  and  instead  of  sweeping  down 
into  the  valleys  by  more  or  less  steep,  smooth  slopes,  as  is  the 
case  with  the  uplands  of  the  bluff  country,  they  are  always 
abruptly  terminated  upon  the  brink  overlooking  the  valleys  from 
a  hight  of  one  hundred  to  two  hundred  feet.  The  quality  of  the 
soil  in  the  valleys  proper  varies  according  to  the  losation.  Immedi- 
ately bordering  the  margins  of  the  streams,  the  low  intervals  occur, 
which  are  made  of  sediments,  sand,  &c.,  the  deposit  of  the  freshets. 
The  lower  terrace  is  usually  enveloped  in  a  fine,  loamy  covering,  of 
remarkable  fertility.  The  earlier  or  higher  terraces,  on  the  con- 
trary, are  composed  of  coarse,  rearranged  materials  derived  from 
the  disintegration  or  wearing  away  of  the  drift  which  once  filled 
these  valleys  —  for  the  valleys  are  evidently  of  very  remote  origin, 
extending  far  back  into  the  past  to  a  time  prior  to  the  glacial  or  Ice 
period.  These  higher  benches  possess  the  warm,  gravelly  soil,  so 
common  in  the  valleys  of  many  of  our  rivers  which  are  tributary  to 
the  Mississippi.  In  the  valley  of  the  North  Raccoon,  below  Granite 
City,  in  the  counties  of  Calhoun,  Carroll,  Green  and  Dallas,  and 
also  in  the  valleys  of  the  South  and  Middle  Raccoons,  the  terrace 
formations  may  be  advantageously  studied.  But  they  are  seen  only 
in  the  valley  of  the  North  Raccoon,  as  at  Adel,  near  Mr.  Gibson's, 
above  New  Jefferson,  and  in  the  vicinity  of  Morlan's,  Calhoun, 
county,  where  they  present  some  of  their  most  conspicuous  and 
diverse-  peculiarities. 

In  connection  with  the  terraces,  interesting  spring  phenom- 
ena are  frequently  observed,  which  have  attracted  considerable 
notice.  In  Greene,  Carroll  and  Calhoun  counties  it  is  not  uncom- 
mon to  meet  with  limpid  streamlets  trickling  down  the  slopes 
toward  the  river,  and  sometimes  they  have  formed  for  themselves 
deep  channels  in  the  loose  material  of  the  surface  over  which  they 
flow.  Tracing  these  little  streamlets  to  their  sources,  they  are 
invariably  found  to  issue  .from  the  gravel  -  bed  immediately  at  the 
point  of  junction  with  the  impervious  blue  clays  of  unmodified  drift. 


REPORT  OP  STATE  GEOLOGIST.  199 

It  is  only  at  those  localities  where  the  sheet  of  gravel  has  been  inter- 
rupted in  its  descent  to  the  lower  levels  of  the  valley,  bringing  to 
the  surface  in  its  stead  (it  may  be  but  a  narrow  band)  the  underlying 
clays  of  the  drift,  that  natural  springs  may  be  expected.  Many 
times  the  springs  issue  almost  at  the  brow  of  the  bluffs,  and  upon 
the  steep  slopes  peaty  deposits  are  in  process  of  formation  from  the 
partial  decomposition  of  the  luxuriant  herbage  growing. in  the  wet 
spots. 

Wells  of  excellent  water  may  be  obtained  at  almost  any  point  by 
sinking  a  shaft  down  through  the  modified  materials  to  the  upper 
surface  of  the  drift  clays,  and  usually  at  a  moderate  depth  from  the 
surface  of  the  ground.  In  the  country  of  the  west  watershed,  rills  of 
water  are  not  obtained  at  so  short  a  distance  below  the  surface ;  there 
the  great  thickness  of  the  bluff  clays  must  be  penetrated  before  the 
lower,  water  -  saturated  gravel  bed  is  reached.  This  would  prove  a 
serious  disadvantage  in  that  section  were  it  not  that  the  bluff  material 
possesses  that  tenacious  quality  which  enables  excavations  to  be  made 
at  any  depth  in  its  mass  without  incurring  the  risks  of  slipping  or 
falling  in  or  the  expense  of  curbing. 

The  distribution  of  forests  upon  both  watersheds  seems  to  have  been 
governed  by  the  influences.  Tlie  annual  fires  which  sweep  the  prairies 
of  the  interior,  unchecked,  have  doubtless  frad  most  to  do  in  pre- 
venting the  general  growth  of  forests  in  this  region.  The  groves  are 
usually  found  in  such  situations  as  afford  them  the  best  natural  pro- 
tection from  the  devastations  of  the  fires.  These  situations  are 
variously  located,  but  usually  the  densest  timbered  lands  are  confined 
to  the  lower  bottoms  bordering  the  streams  and  in  the  deep  gullies 
which  penetrate  the  uplands.  Considerable  bodies  of  timber  skirt 
the  Missouri  bottoms,  but  between  this  belt  and  the  foot  of  the  bluffs 
the  level  stretch  of  the  bottoms  is  interspersed  only  at  long  intervals 
by  lone  cottonwoods  or  clumps  of  willow.  Upon  many  of  the  streams  of 
the  western  watershed  various  belts  or  little  groves  are  not  unfrequent, 
and  they  contribute  the  most  redeeming  features  to  the  landscape. 
Groves  are  not  always  confined  to  the  river  margins,  however,  for  it 
is  not  a  rare  occurrence  to  meet  with  them  upon  the  upland  ridges, 
though  in  these  situations  their  gnarled,  charred  trunks  bear  painful 
evidence  of  their  struggles  with  the  fires.  A  few  miles  north  of 


200  REPORT  OF  STATE  GEOLOGIST. 

Exira,  in  Audubon,  a  considerable  tract  of  the  upland  is  covered 
with  a  scattered  growth  of  oaks  and  underbrush.  And  in  Crawford, 
Harrison  and  Monona  counties,  many  of  the  divides  are  covered  with 
low,  bushy  oaks,  which  spring  from  roots  as  large  as  those  of  the 
mature  forest  tree.  Since  the  settlement  of  this  part  of  the  State, 
fine  groves  of  young  timber  have  grown  up  where  fifteen  years  ago 
the  luxuriant  herbage  of  the  prairies  was  the  only  vegetation.  In 
the  northwest  portion  of  Shelby  county  there  is  a  large  body  of 
forests  on  Mill  creek  and  its  affluents,  which  is  said  to  contain  about 
ten  thousand  acres;  it  is  the  largest  body  of  timber  in  this  region. 
Upon  the  east  watershed  the  valleys  of  the  Raccoon  rivers  and  their 
affluents  afford  considerable  bodies  of  timber  —  enough,  indeed,  to 
supply  the  demand  for  many  years  to  come.  Upon  the  upland  in  this 
portion  of  the  State  handsome  groves  planted  about  the  farms  already 
break  the  continuity  of  the  horizon -like  islands;  and  if  farmers 
would  give  more  attention  to  the  planting  of  artificial  groves,  in  a 
few  years  the  country  would  wear  a  very  'different  and  far  more 
inviting  appearance. 

Fruit-trees  are  said  to  thrive  throughout  this  section  of  the  State; 
the  great  difficulty  to  be  encountered  in  their  cultivation,  is  to  check 
the  rapidity  of  growth  which  is  so  fatal  to  the  hardiness  of  the 
young  tree.  It  must  be  borne  in  mind,  however,  that  there  are  few 
localities  in  the  thirteen  counties  of  this  district  which  have  been 
settled  for  a  longer  period  than  twelve  to  fifteen  years ;  and  expe- 
rience teaches  that  the  introduction  of  fruit -trees  into  anew  country 
is  almost  always  attended  with  many  discouragements.  Now,  that 
nurseries  have  been  established  in  various  parts  of  the  State,  and 
the  trees  acclimated  and  accustomed  to  the  soil,  in  a  few  years  we 
may  reasonably  hope  to  see  as  fine  orchards  upon  our  prairies  as  are 
to  be  met  with  in  any  of  the  older  States  in  the  same  latitude. 

Little  attention  has  been  given  to  the  introduction  of  the  cultivated 
grasses.  But  there  can  be  no  doubt,  in  view  of  the  experience  of  the 
older  settled  portions  of  the  State,  as  to  the  practicability  of  covert- 
ing  immense  tracts  into  the  finest  meadows  in  the  world.  To  -  day, 
however,  the  whole  prairie  is  a  common,  natural  pasturage  and 
meadow.  Upland  and  valley  alike  are  clothed  with  nutritious 
herbage,  affording  a  boundless  range;  and  rivulets,  brooks  and 


REPORT  OF  STATE  GEOLOGIST.  201 

rivers  furnish  a  never  failing  supply  of  water.  In  fine,  there  is 
diversity  enough  to  please  all  tastes  and  suit  all  interests.  There  is 
a  variety  of  soils,  but  the  same  grains  may  be  produced  from  any  of 
them  with  almost  equally  remunerative  results.  And  now,  that 
these  counties  will  soon  enjoy  the  facilities  afforded  by  three  main 
railway  lines  which  traverse  their  territory  east  and  west,  this 
section  of  our  State  will  possess  advantages  second  to  those  of  no 
similar  district,  and  open  to  enterprise  which  it  is  so  capable  profit- 
ably to  sustain. 


REPORT 


OP 


GUSTAVUS    HINRICHS 

STATE   CHEMIST. 


REPORT  OF  CHEMIST. 


To  DR.  C.  A.  WHITE,  State 

SIR —  The  accompanying  Report  contains  the  principal  results  of  my  chem- 
ical work  for  the  survey.    It  will  be  most  convenient  to  divide  this  Report  into 
the  following  chapters,  according  to  the  subjects  treated  of: 
i.    CHEMICAL  REPORT  ON  THE  FUEL  OF  IOWA. 
II.    CHEMICAL  REPORT  ON  THE  WATER  AND  ROCKS  OF  IOWA. 
III.    ON  THE  VALUATION,  COMPOSITION  AND  PROXIMATE  ANALYSIS  OF  IOWA 

COALS. 
IV.    ON  THE  MINERALOGY  OF  IOWA. 

GUSTAVUS  HINRICHS. 
IOWA  CITY,  February  24,  1868. 


CHEMICAL  REPORT  ON  THE  FUEL  OP  IOWA. 


CHAPTER  I. 

In  this  chapter  the  chemical  composition,  physical  properties  and 
heat  -  giving  value  of  our  Iowa  fuel  will  be  given,  particularly  in 
regard  to  coal. 

The  fertile  soil  of  the  State  can  furnish  an  abundance  of  digestible 
fuel,  food  for  the  stomachs  of  the  present  population  and  several 
millions  more.  Below  the  surface  of  this  soil  there  is  an  almost 
inexhaustible  supply  of  very  good  indigestible  fuel,  food  for  the  iron 
stomachs  of  hundreds  of  steam  boilers,  which  one  day  will  be  busy 
in  this  State,  doing  the  hard  work  of  millions  of  hands;  the  joint 
labor  of  the  human  hands,  supported  by  the  product  of  the  soil,  and 
of  the  iron  hands,  fed  by  the  fuel  from  below  the  soil;  this  is  the 
measure  of  the  future  wealth  of  the  State.  Hence  the  prominence 
given  to  the  geological  and  chemical  investigation  of  the  fuel  of  the 
State  in  the  labors  of  the  present  Geological  Survey  of  Iowa. 

I.      ON   THE  ^CLASSIFICATION    OF   FUEL. 

Whenever  any  fuel  is  heated  to  a  certain  temperature,  it  will  burn, 
provided  at  the  same  time  the  air  has  free  access.  The  result  of  this 
combustion  is  a  two  -  fold  one;  the  material  apparently  disappears 
(leaving  only  a  small  amount  of  ashes)  and  heat  is  produced  at  the 
same  time.  In  other  words,  the  fuel  has  been  changed  into  two 
gaseous  products,  carbonic  acid  and  water,  and  in  this  transforma- 
tion heat  was  given  off. 

We  burn  the  fuel  merely  in  order  to  obtain  this  heat  yet  it  can  not 
be  set  free  except  by  converting  the  fuel  into  the  above  mentioned 
two  substances,  carbonic  acid  gas  and  water. 


206  REPORT  OF  STATE  GEOLOGIST. 

These  two  substances  form  a  considerable  part  of  the  atmos- 
phere surrouritling  the  globe,  aiid  every  combustion  increases  this 
amount.  While  thus  the  amount  of  combustible  matter  of  fuels 
is  continually  diminished  by  the  increasing  wants  of  man,  the 
question  naturally  arises  :  can  -not  these  products  of  combustion 
be  re  -  converted  into  fuel  ?  Can  not  fuel  be  manufactured?  No 
doubt  it  can  be  done ;  chemists  have  succeeded  to  decompose  both 
products  above  named,  so  as  to  reproduce  combustibles.  Even  the 
twelve  per  cent  of  pure  carbon  contained  in  our  common  limestone 
can  very  readily  be  extracted  from  the  same  by  chemical  means. 
But  the  power  necessary  for  this  purpose  is  heat,  so  that  unless  this 
heat  be  obtained  at  a  very  low  price,  these  chemical  processes  can 
not  be  utilized  in  the  arts,  or  fuel  can  not  be  manufactured. 

Fortunately  there  is  one  source  of  heat  costing  nothing,  that  is 
the  heat  of  the  sun.  Fortunately  there  is  one  chemical  apparatus, 
costing  nothing,  but  most  eminently  adapted  to  the  work  of 
re  -  decomposing  the  products  of  combustion  given  to  the  air ;  this 
apparatus  is  the  plant.  Just  as  soon  as  but  a  leaflet  is  above 
ground,  the  young  plant  under  the  power  of  the  sun's  ray  com- 
mences its  attack  upon  the  products  of  combustion  contained  in 
the  air ;  the  result  of  this  labor  is  vegetable  matter,  combustible, 
and  in  proportion  as  the  chemical  work  of  the  solar  ray  and  atmos- 
pheric air  goes  on  in  the  cell  of  the  plant,  this  increases  continually. 
It  is  this  action  which  gives  us  our  forests,  our  peat  and  our  coal ! 

Until  heat  can  be  obtained  cheaper  than  the  free  all  -  reaching  ray 
of  the  sun  and  the  raw  -  product  can  be  had  for  less  than  nothing,  the 
present  quotations  of  a  liberal  atmosphere ;  until  then  fuel  will  not 
be  produced  except  as  the  result  of  vegetation. 

Force  being  as  indestructible  as  matter,  we  here  discover  the 
origin  of  the  heat  produced  by  combustion.  For  since  the  heat  of 
the  sun  acting  upon  the  carbonic  acid  and  water  in  the  air  makes  the 
fuel,  this  latter  when  burning  reproduces  not  only  the  former  matter 
(carbonic  acid  and  water,)  but  also  the  force,  heat.  We  may,  there- 
fore, say  that  the  vegetable  tissue  is  air  woven  by  the  sun's  ray. 

It  may  be  well  to  notice  that  this  circulation  of  force  and  matter 
is  perfect ;  solar  heat  and  the  products  of  combustion  produce  the 
combustible ;  this  latter  in  being  burnt,  re  -  produces  both  the 


REPORT  OF  STATE  GEOLOGIST.  207 

materials  of  which  it  was    made,  and  the  heat  which  wove  these 
materials  together. 

In  burning  a  branch  of  last  season's  growth,  we  set  free  the  sun- 
beams of  that  season ;  in  burning  a  tree  a  thousand  years  old,  we 
set  free  the  solar  ray  that  came  to  our  earth  a  thousand  years  ago ; 
in  burning  coal,  the  product  of  a  vegetation  which  flourished  millions 
of  years  ago,  we  liberate  the  beams  of  the  sun  which  came  to  this 
globe  millions  of  years  before  the  appearance  of  man. 

All  our  fuel  is  undoubtedly  of  vegetable  origin.  But  as  vegetation 
is  of  two  tolerably  distinct  kinds,  aquatic  and  terrestrial,  the  fuel 
resulting  must  vary  accordingly.  The  plants  growing  on  the  land 
need  a  special,  firm  texture  to  support  their  own  weight;  those 
growing  in  the  water  are  almost  completely  held  up  by  the  buoyancy 
of  the  liquid,  and  are  therefore  devoid  of  woody  fiber.  As  the 
forests  on  the  land,  so  dominates  the  sea-  weeds  among  the  plants  of 
the  deep  ;  they  are  often  hundreds  of  feet  in  length,  and  of  consider- 
able thickness. 

Plants  may  be  used  as  fuel  immediately  after  being  cut  down 
(our  fire-  wood),  or  they  may  have  been  buried  in  the  sea  or  among 
the  rocks  for  a  greater  or  less  length  of  time  (fossil).  Accordingly 
we  obtain  the  following  general  classification  of  iuel : 


PLANTS. 

GKOWN  ON. 

NAME. 

AGE. 

FUEL. 

Land  •  olants 

Dry  ground  . 

Trees  

Fresh. 

Wood  

Land  -plants 

Dry  ground. 

Trees  

Fossil 

Lignite  and  brown  coal 

Land-  plants 

Wet  ground. 

Mosses,  heather,  etc.  . 

Peat   .. 

Sea-  plants.. 

Sea  -  weeds 

Fossil 

Goal  proper 

bea-  plants. 



8ea-iceed$  .  .  .,  

Fresh  . 

Not  much  used  

All  of  these  varieties  of  fuel  are  found  in  Iowa,  except  Brown  coal 
or  Lignite. 

Just  as  well  as  our  forests  continually  produce  an  increase  of 
wood,  so  we  know  our  peat  -  bogs  annually  to  add  to  the  store  of 
peat ;  and  the  immense  regions  of  sea  -  weeds  in  the  oceans  prove 
that  coal  also  is  continually  being  formed  on  our  globe.  This  view 
was  but  a  few  years  ago  advanced  by  the  distinguished  German 
chemist,  F.  Mohr,  of  Bonn  on  the  Rhine.  In  the  course  of  my 
investigation  of  the  Iowa  coals,  I  have  discovered  several  facts  which 


208  REPORT  OF  STATE  GEOLOGIST. 

add  considerably  to  the  already  overwhelming  evidence  brought  for- 
ward by  the  author  of  this  theory. 

We  shall  now  consider  the  chemical  composition  of  these  various 
fuels,  indicating  the  exact  place  of  our  Iowa  fuels  in  the  series. 
Thereafter  we  intend  to  show  how  the  valuation  or  heating  effect  of 
these  fuels  is  determined.  Finally,  the  results  of  the  several 
analyses  of  Iowa  coals  will  be  given  by  counties. 

It  may  not  be  improper  to  give  a  short  synopsis  of  the  history  of 
the  coal,  particularly  as  this,  after  Mohr's  labors,  appears  remarkably 
simple,  and  also  because  our  Iowa  coal-field  seems  particularly 
adapted  to  prove  the  correctness  thereof. 

In  order  to  make  this  chapter  of  interest  to  the  general  reader,  I 
shall  leave  out  everything  of  an  abstruse  nature ;  but  for  the  sake 
of  completeness,  these  matters  will  be  given  in  a  separate  chapter. 

II.       ON   THE    COMPOSITION   OF   FUEL. 

The  chemical  elements  which  constitute  by  far  the  greatest  portion 
of  all  fuel,  are  Carbon,  Hydrogen,  and  Oxygen. 

The  first  of  these  we  have  almost  pure  in  charcoal;  it  burns 
without  producing  any  flame  while  producing  a  very  high  degree  of 
heat.  The  greater  the  proportion  of  carbon  in  any  fuel,  the  deeper 
black  will  be  the  color  of  the  same,  and  the  more  intense  will  be  the 
heat  produced  by  its  combustion,  but  the  less  flame  will  result. 

The  second  of  these  elements,  hydrogen,  is  the  very  opposite;  not 
solid  but  a  gas,  and  even  the  lightest  body  we  know  ;  when  burning 
it  is  all  flarne,  producing  a  great  quantity  but  relatively  not  so  high  a 
degree  of  heat,  as  carbon.  Hydrogen  constitutes  one- ninth  by  weight 
of  water,  about  one- sixth  by  weight  of  common  illuminating  gas. 
Hence  the  greater  the  per  centage  of  hydrogen  in  any  fuel,  the  more 
flame  when  burning.  That  part  of  the  burning  fuel  which  is  suffi- 
ciently heated  will  decompose,  giving  off  its  hydrogen  and  some  carbon, 
as  a  gaseous  substance,  more  or  less  like  illuminating  gas ;  as  soon 
as  this  meets  the  air,  supplied  by  means  of  proper  draft,  it  will  burn 
constituting  the  flame  of  all  these  combustibles. 

The  third  principal  element  of  our  fuels,  oxygen,  may  be  considered 
an  unproductive  part  of  the  fuel.  When  constituting  a  part  of  the 


REPORT  OF  STATE  GEOLOGIST.  209 

fuel,  it  costs  a  corresponding  amount  to  us,  while  in  the  air  we  could 
have  it  free  of  cost ;  and  as  the  heat  of  combustion  only  results  from 
the  carbon  or  hydrogen  uniting  with  oxygen,  it  is  furthermore 
evident,  that  any  oxygen  united  with  these  other  elements  in  the  fuel 
prevents  those  parts  thus  already  provided  with  oxygen  from  pro- 
ducing any  heat.  A  fuel  is  therefore  so  much  the  better  the  less  the 
amount  of  oxygen  it  contains. 

Omitting  for  the  present  the  consideration  of  those  elements 
present  in  small  quantities,  we  may  express  the  average  composition 
of  the  various  fuels,  referred  to  one  hundred  carbon,  in  the  following 
figures : 


FUEL  -DRIED. 

Carbon. 

Hydrogen. 

a 

OJ 

bC 
>, 

X 
0 

1 

Wood  

100 

18 

90 

90S 

Peat       •                            

100 

110 

60 

170 

Lignite             

100 

8 

30 

138 

Bituminous  Coal  

100 

M 

15 

122 

Anthracite.  . 

100 

0 

5 

107 

The  fuels  abundant  in  Iowa  are  in  italics. 

According  to  the  remarks  just  made,  it  will  require  much  more 
wood  than  coal  to  produce  the  same  heating  effect,  on  account  of  the 
great  proportion  of  oxygen  in  the  former.  The  amount  of  hydrogen 
corresponding  to  100  carbon  gives  a  fair  representation  of  the 
inflammability  of  the  fuel. 

The  fuel,  as  commonly  used,  is  not  artificially  dried,  but  contains 
a  greater  or  less  amount  of  moisture.  A  portion  of  the  heat  devel- 
oped by  combustion  of  the  fuel  is  therefore  wasted  in  driving  off  the 
moisture.  All  fuel,  furthermore,  contains  a  very  noteworthy  amount 
of  ashes,  which  also,  in  various  ways,  diminishes  the  effectiveness  of 
the  fuel.  Nor  can  we  finally  consider  the  fuel  as  merely  constituted 
of  the  above  elements  thoroughly  mixed  up,  they  are  chemically 
combined.  To  increase  the  difficulty  still  more,  it  has  hitherto  not 
been  possible  to  ascertain  the  exact  way  in  which  these  elements  are 
combined.  Thus  it  seems,  that  very  little  can  be  ascertained  chem- 
ically in  regard  to  the  exact  value  of  the  various  fuels. 
27 


210  REPORT  OF  STATE  GEOLOGIST. 

But  when  fuels  are  used  for  heating  purposes,  they  are,  as  men- 
tioned above,  always  more  or  less  decomposed  before  they  are  totally 
consumed.  The  heat  in  the  fire  -  place  decomposes  the  fuel  into  a 
volatile  and  a  non- volatile  portion;  the  former  when  burning  con- 
stitutes the  flame,  the  latter  when  cooled  constitutes  the  coke,  (or,  in 
the  case  of  wood,  charcoal.)  Hence,  it  is  not  at  all  the  fuel  as  it  is 
thrown  upon  the  grate  that  burns,  but  rather  the  products  resulting 
from  the  fuel  when  exposed  to  the  heat  of  the  fire-place.  Although 
we  therefore  may  be  ignorant  of  the  exact  arrangements  of  the 
elements  in  the  cold  fuel,  we  may,  nevertheless,  be  able  to  estimate 
its  heating  effects,  if  we  succeed  in  ascertaining  the  products  wherein 
the  fuel  is  decomposed  previous  to  its  actual  combustion. 

Now  this  is  what  the  so  -  called  proximate  analysis  of  fuel  attempts 
to  do.  By  exposing  the  fuel  to  heat,  being  careful  to  exclude  the 
air  from  it,  we  ascertain  the  amount  of  volatile  matter  in  the  fuel ; 
this  subtracted  from  the  total  weight  taken,  gives  the  per  centage  of 
coke.  By  separate  operations  both  the  amouit  of  moisture  and  of 
ashes  is  determined;  subtracting  the  former  from  the  volatile,  gives 
the  amount  of  volatile  combustible  matter,  which  I  for  brevity  call 
bitumen;  subtracting  the  per  centage  of  ashes  from  that  of  the  coke, 
we  obtain  the  amount  of  non  -  volatile  combustible  matter,  which  is 
almost  pure  carbon,  and  therefore  is  called  carbon.  By  means  of  an 
extensive  series  of  experiments,  I  have  succeeded  in  porfecting  this 
method  of  analysis  to  be  fully  equal  in  exactitude  to  that  of  the 
elementary  analysis ;  so  that  the  analysis  made  by  me  will  not  only 
have  a  relative  value,  but  fix  the  absolute  value  of  the  coals  analyzed. 
The  detail  of  this  method  and  the  investigation  leading  thereto  ap- 
peared in  the  American  Journal  of  Mining.  [See  Chapter  III.] 

As  an  average  from  which  the  various  samples  of  Iowa  coals  but 
slightly  deviate,  I  may  give  the  following  percentage  composition : 

COMPOSITION. 


VOLATILE  —  PER  CENT. 

COKE  —  PER  CENT. 

Bitumen 

45 

Carbon 

45 

Moisture  

05 

Ashes      

05 

Total.. 

,50 

Total.. 

.50 

Total  combustion,  90  per  cent. 


REPORT  OF  STATE  GEOLOGIST.  211 

In  the  Report  of  Prof.  Whitney  (vol.  1,  pt.  1,  page  399)  it  is  stated 
that  the  Iowa  coals  contain  from  45  to  50  per  cent  of  carbon.  This 
statement  has  been  copied  in  Bailey  and  Hair's  popular  "  Iowa  State 
Gazetteer"  Chicago,  1865,  page  22.  The  actual  per  centage  of  car- 
bon given  by  Whitney  on  the  subsequent  pages,  as  the  result  of  his 
own  analyses,  range  all  the  way,  and  regularly,  from  39  to  55  per 
cent;  that  is,  instead  of  varying  only  5  per  cent,  the  variation  is 
fully  16i ! 

In  commencing  the  more  critical  study  of  the  Iowa  coals,  I  very 
soon  discovered  that  notwithstanding  this  great  variation  in  the  com- 
position of  the  raw  coal,  the  combustible  itself  varied  but  very  little, 
being  composed  of  about  40  of  bitumen  and  54  of  carbon.  This 
discovery  was  first  mentioned  by  me  in  the  "report  of  progress"  for 
1866,  and  is  in  detail  published  in  the  American  Journal  of  Mining, 
for  November  30,  1867.  [See  Chapter  III.] 

The  direct  consequence  of  this  discovery  is  that  the  heating  effect 
of  our  various  Iowa  coals  is  measured  "by  their  per  centage  of  com- 
busiible  matter]  for  if  this  latter  is  of  the  same  composition  in  our 
Iowa  coals,  it  follows  that  the  heating  effect  is  proportional  to  the 
amount  of  this  combustible.  The  per  centage  of  combustible  in  Iowa 
coals  I  have  therefore  called  the  value  of  these  coals. 

Furthermore,  two  coals  will  have  the  same  heating  effect,  if  they 
contain  the  same  weight  of  this  combustible  ;  hence  I  call  such  weights 
of  the  various  Iowa  coals  as  contain  the  same  amount  (100)  of  com- 
bustible matter,  the  caloric  equivalents  of  these  coals. 

If  we  had  a  certain  weight  of  the  pure  combustible  contained  in 
Iowa  coals,  but  free  from  both  ashes  and  moisture ;  if  this  weight 
could  be  had  for  one  dollar,  then  the  raw  Iowa  coal,  containing  on 
the  average  90  per  cent  of  this  combustible,  would  be  worth  90  cents 
for  just  that  weight,  and  111  pounds  .of  the  same  coal  would  produce 
the  same  amount  of  heat,  as  would  be  obtained  by  burning  100  pounds 
of  the  pure  combustible. 

Since  this  is  an  entirely  new  method  of  valuation  of  coals,  it  will 
be  necessary  to  give  an  example  in  order  to  be  fully  understood  by 
the  reader: 

For  instance,  the  coal  from  Henry  Shock  &  Co.'s  mine  on  section 


212  REPORT  OF  STATE  GEOLOGIST. 

eight,    township    seventy -two,    range   fourteen,   near    Chillicothe, 
Wapello  County,  gave  by  my  analysis : 


No.  346.     Top. 

No.  371.    Bottom. 

Specific  jjravitv 

1  361 

1  308 

Weight  of  1  cubic  foot.  .  . 

84.82  Ibs       • 

81.50  Ibs. 

Volatile  matter  
Coke      

46.36  per  cent. 
53.64  per  cent. 

47.79  per  cent. 
52.21  per  cent. 

Bit  urn  en 

38  55  per  cent 

41  67  per  cent 

Carbon                       

46  47  per  cent 

48  34  per  cent. 

COMBUSTIBLE 

Ashes  (red) 

85  02  per  cent. 
7  17  per  cent 

90  01  per  cent- 
(white)      3  87  per  cent. 

Moisture  '  

7  81  per  cent. 

612  per  cent. 

100.00  per  cent. 

100.00  per  cent. 

REFERRED  TO  THE  COMBUSTIBLE  — 100  PER  CENT. 


Bitumen  

4536 

46  32 

Carbon               . 

5464 

53  68 

Ashes       . 

844 

430 

Moisture  

9.19 

6.80 

Eouivalent  .  . 

117.63 

111.00 

It  may  be  seen  from  this  analysis  that  the  combustible  of  the  top 
and  bottom  part  of  this  coal -bank  is  very  nearly  the  same;  con- 
taining about  forty -six  parts  of  bitumen  in  each  one  hundred  of 
combustible.  The  top  coal  contains  eighty -five  per  cent  of  com- 
bustible, the  bottom  coal  ninety  per  cent  of  the  same ;  hence,  if  a 
certain  weight  of  the  top  coal  is  -worth  eighty  -  five  cents,  the  same 
weight  of  the  bottom  coal  will  be  worth  ninety  cents,  for  heating 
purposes ;  the  same  weight  of  the  pure  combustible  would  be  worth 
one  dollar.  This  is  what  is  meant  by  saying  the  per  centage  of  the 
combustible  expresses  the  value  of  our  Iowa  coals. 

Again,  in  order  to  get  one  hundred  pounds  of  pure  combustible, 
it  is  necessary  to  take  nearly  one  hundred  and  eighteen  pounds  of 
the  top  coal,  or  one  hundred  and  eleven  pounds  of  the  bottom  coal. 
In  other  words,  one  hundred  and  eleven  pounds  from  the  bottom  of 
this  mine  contains  as  much  of  the  heating  material,  or  are  capable 
of  yielding  as  much  heat,  as  one  hundred  and  eighteen  pounds  from 
the  top  part  of  the  mine;  that  is,  one- hundred  and  eighteen  of  the 
top  coai  are  equivalent  in  regard  to  their  heating  or  caloric  effect  to 
one  hundred  and  eleven  pounds  of  the  bottom  coal.  This  is  what  is 
meant  by  the  caloric  equivalent  given  in  my  analyses  of  Iowa  coals. 


EEPORT  OF  STATE  GEOLOGIST.  213 

Both  of  these  two  values,  on  which  the  practical  importance  of 
the  analyses  of  Iowa  coal  depends,  are  the  result  of  my  own  inves- 
tigations. They  were  therefore  not  given  in  any  analyses  of  Iowa 
combustibles  previous  to  my  own. 

Finally,  it  will  be  observed,  that  the  color  of  the  ashes  of  the  top 
coal  is  red  ;  that  of  the  bottom  coal  is  white.  The  red  color  in  the 
ash  being  due  to  iron  oxide  in  the  same,  resulting  from  pyrites  (iron 
combined  with  sulphur)  in  the  coal,  it  is  evident  that  the  top  coal 
contains  a  considerable  amount  of  sulphur,  the  bottom  coal  hardly 
any.  Hence  the  bottom  coal  is  good  for  blacksmithing  purposes, 
the  top  coal  not ;  if  used  for  mere  heating  purposes,  the  top  coal 
will  be  more  destructive  to  grate  and  boiler  than  the  bottom  coal. 

The  guide  of  the  analyses  in  regard  to  the  amount  of  coke  or  gas 
that  the  coals  may  yield  was  given  in  the  older  analyses  also  ;  but 
since  my  analyses  are  made  according  to  a  method  giving  strictly 
reliable  results,  the  estimates  here  given  for  gas  and  coke  may  prove 
a  more  safe  guide  for  those  who  either  would  manufacture  coke,  in 
order  to  enable  them  to  ship  coal  to  greater  distances,  or  who  would 
select  a  coal  for  a  gas  works. 

I  have  dwelled  thus  lengthily  upon  this  sample  in  order  that  the 
people  may  be  enabled  to  understand  the  meaning  of  the  figures 
given  as  the  result  of  my  analyses  of  Iowa  coal,  particularly  since 
these  two  expressions  of  value  and  equivalence  never  before  have 
been  connected  with  proximate  analyses  of  coal.  This  valuable 
practical  result  I  claim  as  one  discovered  during  the  progress  of  the 
Geological  Survey  of  Iowa. 

In  order  to  compare  our  Iowa  coal  with  those  of  other  parts  of  the 
world,  so  as  to  test  the  popular  opinion  that  our  Iowa  coals  are  of 
an  inferior  quality,  I  have  analyzed  the  following  seven  samples  of 
fuel,  contained  in  my  private  cabinet  of  minerals.  For  the  sake  of 
completeness,  I  have  also  added  my  analysis  of  the  most  volatile  solid 
fuel,  asphaltum.  It  must  be  observed,  that  these  analyses  are  com- 
parable, having  all  been  executed  according  to  my  improved  method. 


211 


REPORT  OF  STATE  GEOLOGIST. 
COMBUSTIBLE  — 100. 


NAME  AND  LOCALITY. 

0 

i 

02 

8 

j 

f 

a 

02 

'B 

a 

CB 

0 

C"* 

'* 

O 

s 

<j 

5? 

Ed 

> 

Alsphaltum   ... 

26 

•  74 

4 

V 

104 

96 

Peat  from  Ireland 

36 

64 

2 

16 

118 

85 

Bituminous  wood  from  Salzhausen     Hessia 

81 

69 

5 

10 

115 

87 

Brown  coal  from  Arbesan  Bohemia              

86 

64 

3 

11 

114 

88 

Brown  coal,  from  Biiin,  Bohemia  

40 

67 

16 

00 

81 

Bituminous  coal  from  Beutaen   Silisia 

51 

49 

21 

5 

i  126 

80 

IOWA  COALS   average  ..              ...    .. 

50 

50 

5 

110 

90 

Cannel  coal,  from  Wigan,  England  

61 

89 

10 

112 

89 

Anthracite,  from  Pennsylvania   . 

94 

6 

2 

2 

104 

96 

[For  the  sake  of  perspicuity  the  decimals  have  not  been  given.] 

The  excess  of  the  equivalent  above  100  expresses  the  amount  of 
impurities  [ashes  and  moisture]  in  the  coal.  For  the  same  kind  of 
fuel  its  heating  effect  will  therefore  be  the  greater  for  equal  weights, 
the  less  this  equivalent  exceeds  one  hundred.  Now  in  this  regard 
our  Iowa  coals  are  as  good  as  any,  for  the  average  shows  only  ten 
parts  of  impurities  for  100  parts  of  combustible.  Though  in 
particular  cases  this  amount  is  frequently  exceeded,  it  is  also  very 
often  much  less.  Thus  the  coal  from  the  top  of  the  bank  at  Business 
Corner,  Van  Buren  county,  has  an  equivalent  of  only  102.73  :  that  is, 
for  each  100  of  combustible  this  coal  contains  only  2}  of  foreign 
matter,  or  less  than  the  Anthracite  analyzed.  The  equivalent  of  the 
coal  from  the  bottom  of  Richardson's  mine,  two  miles  west  of  Fairfield, 
Jefferson  county,  is  a  little  lower  yet,  only  102.87,  and  indeed  the 
lowest  of  any  Iowa  coals  yet  analyzed  ;  that  is,  it  is  the  purest  of  all 
samples  investigated,  containing  not  even  2J  parts  of  non  -  combusti- 
ble matter  for  each  100  of  combustible,  or  less  than  one  pound  in 
forty  pounds  of  pure  combustible  matter. 

Nor  is  the  kind  of  ashes  in  our  Iowa  coals  of  a  more  obnoxious 
quality  than  that  of  other  coals.  The  ashes  from  the  bottom  coal  of 
Henry  Shock  &  Go's  mine,  Wapello  county,  or  from  the  bottom  coal 
of  the  Iowa  Coal  Company's  mine  at  Oskaloosa  Station,  Mahaska 
county,  and  from  many  other  samples  of  Iowa  coal,  is  as  pure  white 
as  the  ashes  from  the  English  cannel  coal,  analysis  of  which  is  above 
given.  Nor  is  the  ash  of  any  Iowa  coal  more  ferruginous,  or  the 
corresponding  coal,  more  sulphurous  than  corresponding  coal  from 


REPORT  OF  STATE  GEOLOGIST. 


215 


other  regions;  the  simple  fact  of  the  matter  is,  that  everywhere  we 
have  both  poorer  and  better  qualities  of  coal  in  these  respects,  and 
while  none  of  our  Iowa  coals  is  worse  than  poor  coals  from  other 
countries,  there  are  no  bituminous  coals  better  in  any  country  than 
the  best  coals  of  our  State,  both  in  regard  to  the  amount  and  quality 
of  the  impurities  of  the  fuel. 

Again,  it  will  be  observed  that  the  amount  of  carbon  in  the  various 
combustibles  analyzed  ranges  from  40  to  94.  The  average  would  be  : 

Peat  and  brown  coal,  40  per  cent  carbon. 
Bituminous  coal,  50  per  cent  carbon. 
Anthracite,  above  90  per  cent  carbon. 

It  therefore  appears  that  our  Iowa  coals  are  as  rich  in  carbon  as 
the  average  of  bituminous  coals  th-3  world  over.  We  have  among 
the  numerous  samples  analyzed  found  one  sample  almost  identical 
with  the  genuine  cannel  coal  from  Wigand,  England,  mentioned 
above;  this  coal  is  from  the  top  of  the  Alpine  Coal  Company's  mine, 
at  Alpine,  on  the  Des  Moines  river,  in  the  southeastern  township  of 
Wapello  county.  This  will  become  plain  by  comparing  the  results  of 
my  analysis  : 


CANNEL   COAL. 

From   Al- 
pine, (top, 
No.  336.) 

From 
Wigand, 
England. 

Bitumen        

40.37 
59.53 
100.00 
8.09 

4.72 
112.81 
88.65 

39.05 
60.95 
100.00 
[white]  9.53 
3.39 
112.92 
8856 

Carbon   ".  

Combustible                                              .  .             

Aslie«  [grey]                                       

Moisture     

Eo.uiv8.lent                                                             ...           ... 

Value  

The  correspondence  in  the  composition  of  these  two  samples,  the 
one  from  England,  the  other  from  the  Des  Moines  Valley,  is,  to  say 
the  least,  most  remarkable  ;  at  any  rate  this  Iowa  coal  is  as  good  as 
the  English  cannel  coal  here  analyzed. 

The  column  headed  "  Value  "  in  the  preceding  table  has  not  the 
same  signification  as  it  has  for  our  Iowa  coals,  for  the  per  centage  of 
bitumen  in  the  combustible  of  these  fuels  varies  very  much,  so  that 


216  REPORT  OF  STATE  GEOLOGIST. 

an  equal  per  centage  of  combustible  for  the  various  kind  of  fuel  does 
not  imply  an  equal  heating  effect.  Indeed  we  know,  that  while  one 
pound  of  carbon,  by  complete  combustion,  will  produce  heat  sufficient 
to  heat  eighty  -  one  pounds  of  water  from  the  freezing  to  the  boiling 
point,  or  to  convert  about  twelve  pounds  of  water  into  steam,  the 
various  gases  constituting  the  volatilized  bitumen  have  a  different 
heating  power  —  some  producing  less,  others  producing  more  heat 
than  an  equal  weight  of  pure  carbon. 

According  to  the  determination  of  the  late  Prof.  Forchhammer,  of 
Copenhagen,  as  stated  in  his  lectures,  one  pound  of  the  various  fuels 
will  by  combustion  raise  the  temperature  of  the  following  number  of 
pounds  of  water  from  the  freezing  to  the  boiling  point: 

Wood,  air  -  dry 22  ft>s 

Peat 25  lt>s 

Brown  coal . .  29  to  36  libs 

Pit  coal. . .  .(Bitumir  ous  coal). . . , 50  to  60  K>3 

Anthracite '. 70  ibs 

While  these  figures  state  the  amount  of  heat  that  can  be  obtained, 
but  which  actual  practice  falls  very  much  short  of,  we  have  some 
experiments  of  the  Prussian  Chemist  Brix  determining  the  number  of 
pounds  of  water  actually  converted  into  steam  by  means  of  one 
pound  of  fuel  in  the  same  heating  apparatus ;  his  results  were : 

Wood 4  to  5  R)s 

Peat 5  to  6  fts 

Brown  coal 5  to  6  R>3 

Bituminous  coal 6to7  ft>s 

Charcoal,  dry 7£  Ibs 

Since  one  pound  of  pure  ca.rbon,  if  completely  utilized,  would 
convert  twelve  pounds  of  water  into  steam,  this  last  figure  shows 
how  much  even  carefully  conducted  experiments  fall  behind  this 
theoretical  standard. 

By  means  of  these  figures  we  see,  that  for  equal  weights  the  heat- 
ing effect  is  smallest  for  wood,  greater  for  peat,  still  greater  for 
brown  coal,  and  that  bituminous  coal,  or  rather  pit  coal  (steinkohle 
of  the  Germans)  is  only  surpassed  by  anthracite  in  its  heating 
effect. 


REPORT  OF  STATE  GEOLOGIST.  217 

Since  now  my  extensive  analyses  have  proved  that  our  Iowa 
coals  are  fully  equal  to  the  average  of  bituminous  coal,  we  must  con- 
sider the  popular  opinion  that  Iowa  coals  are  not  as  good  as  others, 
a  mistake  caused  by  comparing  our  bituminous  coal  to  a  fuel  like 
anthracite.  The  fact  is,  that  the  composition  and  hence  the  value 
of  the  coals  of  this  State,  as  far  as  investigated,  is  fully  equal 
to  that  of  the  true  stone  coal  all  the  world  over ;  and  if  the  work- 
able banks  in  our  State  are  not  as  thick  as  those  of  some  other 
countries,  wre  have  them  close  at  hand  and  can  run  the  railroad  -  track 
right  into  the  mine,  while  in  those  otherwise  more  favored  regions 
they  have  to  dig  two  thousand  feet  deep  in  order  to  reach  the  coal. 

III.      GENERAL   RESULTS    ON   THE   SOUTHEASTERN    PART    OP    THE    IOWA 

COAL  -  FIELD. 

In  the  course  of  my  reductions  of  the  analyses  of  Whitney  and 
Blaney,  I  frequently  found  a  considerable  difference  between  the 
composition  of  the  upper  and  lower  part  of  the  same  coal  bank.  At 
the  same  time  I  discovered  a  remarkable  uniformity  in  regard  to  the 
composition  of  coal  from  various  parts  of  the  field,  and  reported  the 
same  in  a  paper  inserted  in  the  American  Journal  of  Mining  for 
November  30.  [See  Chapter  III].  My  new  method  of  reduction  in 
revealing  such  differences  in  the  analyses  of  others,  appeared  to  me 
to  be  a  proper  instrument  to  apply  to  my  own  systematic  analyses  in 
order  to  discover  the  general  law  in  regard  to  the  deposit  of  carbon- 
aceous matter  in  the  vertical,  if  any  exists. 

The  State  Geologist  having  selected  specimens  for  analyses  both 
from  the  upper  and  lower  parts  of  each  coal  -  bank  the  material 
thus  placed  in  my  hands  is  very  considerable  and  most  valuable  as  a 
systematic  collection  representing  the  mineral  fuel  of  Iowa.  Each 
specimen  bears  a  green  circular  label  with  a  number  by  means  of 
which  its  full  history  can  be  obtained  from  the  catalogue ;  when 
analyzed,  a  rhombic,  red  label  is  added,  with  the  same  number,  thus 
at  the  same  time  increasing  the  security  against  any  possible  loss  of 
the  history  of  the  specimen.  It  is  only  in  this  way  that  a  collection 
of  coal  is  worth  all  it  costs  to  accumulate  the  same.  In  regard  to 
^ 


218 


REPORT  OF  STATE  GEOLOGIST. 


the  present  collection  of  Iowa  coals,  beside  securing  the  permanent 
value  of  the  specimens  as  such,  they  are  also  the  means  which  may 
be  used  at  any  time  to  test  the  correctness  of  my  analyses. 

The  portion  of  the  coal  -  field  from  which  coal  has  been  analyzed 
forms  a  strip  of  land  about  twenty  miles  broad  in  the  direction  of 
the  Des  Moines  river  from  Farmington  to  Knoxville;  this  being  a 
distance  of  more  than  eighty  miles,  the  part  chemically  investigated 
covers  about  1,600  square  miles  of  our  Iowa  coal  -field.  Of  course 
many  more  analyses  will  have  to  be  made  even  for  this  portion  of 
the  field ;  beside  this  investigation  will  have  to  be  extended  to  the 
whole  of  the  coal  -  field. 

The  most  important  result  of  my  investigations  consists  in  the 
discovery  of  two  chemically  distinct  banks  of  coal,  traced  the  one 
for  seventy,  the  other  for  fifty  miles  along  the  Des  Moines  river. 
This  is,  as  far  as  I  know,  the  first  time  that  the  chemical  analysis  of 
specimens  in  the  laboratory  has  been  the  means  of  tracing  a  coal- 
bank  across  the  field. 

Bank  First.  —  The  existence  of  this  bank  I  base  upon  the  identity 
of  the  coal  in  mines,  both  at  the  bottom  and  at  the  top  of  the  same. 
In  the  following  I  give  the  final  result  of  my  analyses  of  these  speci- 
mens, referred  to  the  combustible  taken  as  100.  The  "  numbers  " 
are  those  put  on  the  labels  of  the  specimens  in  the  collection ;  th^ 
first  always  referring  to  the  sample  from  the  upper ;  the  second  to 
that  from  the  lower  part  of  the  coal  bank  : 


NO. 

MINE. 

DISTANCE 

COUNTY. 

BITUMEN. 
TOP.  |  BOT. 

330,329 
385,396 
405,343 

1 

Carmine's  bank  . 

20  miles  
50  miles  

Van  Burcn 

46.4    52.6 
409!  52.4 
47.2!  51.8 

46.91  52.3 

Young  &  Stubbs'  bank.  .  . 
]N  ossacdan's  bank 

Jefferson  

Marion 

lean  .  . 

Here,  and  in  all  subsequent  tables,  I  give  only  one  decimal  to  the 
number  of  per  cent;  that  is  fully  as  much  as  can  be  relied  upon,  for 
this  decimal  expresses  the  composition  within  the  fractional  of  one 
thousandth. 


REPORT  OP  STATE  GEOLOGIST. 


219 


It  will  be  seen  that  Young  &  Stubbs'  bank,  both  at  the  top  and  at 
the  bottom,  coincides  with  this  mean  ;  at  Carmine's  bank  the  two 
figures  are  a  little  farther  apart ;  at  Nossaman's  they  are  a  little 
nearer  together.  The  mean  difference  between  the  bottom  and  top 
coal  is  5.4  per  cent  of  bitumen  more  at  the  bottom  than  at  the  top. 

In  regard  to  the  amount  and  quality  of  the  ashes  I  find  (always 
for  one  hundred  combustible)  : 


AMOUNT. 

COLOR  OF  ASHES. 

MINE. 

TOP.  EOT. 

TOP. 

BOTTOM. 

8.0 
4.3 

_09 

6.4 

9.5 
12.5 
22.5 

14.5 

Blackish  brown.... 
Brown 

Light  crev 

Young  &  Still 
Nossaman's 

)bs' 

Whitish  pink 

*  Reddish  pink.  . 

White  and  pink.  .  . 
Whitish  

Mean  

Reddish...  

From  this  table  it  will  be  seen  that  the  top  coal  always  contains 
less  ashes  than  the  bottom  coal,  while  at  the  same  time  the  ash  of 
the  bottom  coal  is  more  white,  and  that  of  the  top  coal  more  reddish. 

When  it  is  considered  how  many  circumstances  have  to  conspire  in 
order  to  produce  so  close  a  harmony  in  so  many  particular  quantities 
relating  to  these  three  mines,  it  will  be  understood  how  I  am  led  to 
consider  this  agreement  a  proof  of  the  sameness  of  the  coal  bank. 

Sank  Second. — The  corresponding  tables  for  this  bank  are  : 


NO. 

MINE. 

DISTANCE. 

COUNTY. 

BITUMEN. 

TOP 

EOT. 

370,360 

390,384 
348,350 

Me 

Brown  &  Godfrey's  
Iowa  Coal  Co  's 

20  miles  
25  miles 

Wapeilo  

51.3 
50.4 
49.4 

46.4 
45.2 
47.0 

Mahaska            .... 

lioberts  and  l^isher's 

Marion  

an  

50.4 

46.2 

The  law  of  variation  in  this  bank  is  the  reverse  of  what  it  is  for 
bank  first ;  for  while  in  bank  first,  the  bottom  coal  contains  5.4  more 
of  bitumen  per  hundred  combustible,  than  the  top  coal,  here  in  bank 
second,  the  top  coal  contains  3.6  more  than  the  bottom  coal.  It  will 
further  be  observed  that  the  top  coal  of  bank  first  (46.9)  is  almost 
identical  with  the  bottom  coal  of  bank  second  (46.2). 


220  REPORT  OP  STATE  GEOLOGIST. 

For  the  ashes,  we  have  in  bank  second : 


MINE. 

AMOUNT. 

( 

TOP. 

:OLOR. 

TOP.  (BOTTOM. 

BOTTOM. 

Brown  &  Godfrey's 

9.4 
2.9 

7.1 

12.0 

7.4 
9.5 

9.7 

Red 

Pale  pink  
White 

Iowa  Coftl  Company's     

Br'wnish 
Red  

Reddish. 

Roberts  &  Fisher's     

Brownish  
More   whitish 

Mean  .  . 

6.5 

In  regard  to  the  ashes,  bank  second  follows  the  same  law  as  bank 
first ;  the  lower  layers  contain  the  most  ashes,  but  the  least  of  iron 
(red  color)  in  the  same. 

From  this  circumstance,  I  conclude  that  bank  second  belongs 
above  bank  first ;  the  correctness  of  this  conclusion  is  further  con- 
firmed by  the  fact  that  the  upper  part  of  bank  first  and  the  lower 
part  of  bank  second  not  only  agree  in  the  main  per  centage  of  bitu- 
men (which  is  respectively  46.9  and  46.5),  but  that  they  actually 
vary  in  the  same  manner,  increasing  in  bitumen  toward  the  north- 
west ;  the  first  bank,  top,  from  46.5  to  47.2,  and  bank  second,  bot- 
tom, from  46.4  to  47.4. 

The  mean  of  ashes  in  bank  first  is  10.1 ;  in  bank  second  8.8,  and 
as  in  each  bank  the  amount  of  ashes  increases  downward,  this  is  a 
further  proof  that  bank  second  is  above  bank  first. 

According  to  these  chemical  investigations  of  the  lower  Des 
Moines  coal -field,  the  following  may,  in  the  absence  of  my  drawings, 
be  given  as  a  representation  of  this  field  : 


FOE   100    COMBUSTIBLE. 


BANK. 


PART. 


BITUMEN. 


ASHES. 


COLOR  OF  ASHES 

red 


Bank  2'     \  (increase  upward) 

or  upper,     (  bottom  N  (intermediate 

j- 46 8 -j    colors 

Bank  1,  or  {'<*••••  *         (increase  downward) 

'er'      (  bottom 52 10 .white 

As  far  as  I  have  examined  the  specimens,  the  Van  Buren  county 
and  the  Jefferson  county  mines  belong  all  to  the  first  or  lower  bank. 
All  of  the  samples  analyzed  from  mines  in  the  counties  of  Wapello, 
Mahaska  and  Marion,  belong  to  the  second  or  upper  bank,  excepting 
Nossaman's  bank  in  Marion  county. 


REPORT  OF  STATE  GEOLOGIST.  221 

The  amount  of  coal  easily  accssible  along  the  border  of  the  coal- 
field is  immense ;  but  the  great  future  of  this  commonwealth  depends 
still  more  upon  the  continuation  of  these  riches  under  the  overlying 
rocks  toward  the  deeper  portions  of  the  coal -basin.  In  the  accu- 
rate and  comprehensive  study  of  the  coal  I  believe  we  have  now  a 
very  effective  auxiliary  for  the  exploration  of  this  basin ;  and  it  may 
therefore  be  expected  that  this  auxiliary  will  be  made  available. 


222 


REPORT  OF  STATE  GEOLOGIST. 


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224 


REPORT  OF  STATE  GEOLOGIST. 


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REPORT  OF  STATE  GEOLOGIST.  225 

All  terms  used  in  the  preceding  tables  having  been  explained  in 
the  second  article  on  the  fuel  of  the  State,  only  a  few  remarks  en 
the  figures  themselves  need  be  added. 

The  means  here  given  for  each  county  are  of  course  liable  to 
change  by  the  investigation  of  more  mines  in  each  county,  but  the 
fact  that  the  samples  analyzed  were  not  selected,  but  rather  taken  at 
random,  together  with  the  fact  that  the  final  results  indicate  a  gradual 
change  in  the  mean  of  the  coals  from  the  consecutive  counties,  rather 
proves  that  the  results  thus  far  obtained  will  not  be  materially  altered 
by  increasing  the  number  of  specimens  analyzed  for  each  county. 

From  the  last  table  it  will  be  seen  that  the  Iowa  coals  are  most 
bituminous  in  Van  Buren  county,  and  that  the  amount  of  bitumen 
decreases  slowly  in  a  direction  up  the  Des  Moines  river.  The  same 
is  true  in  regard  to  the  per  centage  of  volatile  matter.  On  the 
whole,  the  coals  from  lower  down  the  river  therefore  are  more  baking 
and  also  better  for  gas  -  making.  At  the  same  time  they  contain  the 
smallest  per  centage  of  both  ashes  and  moisture,  that  is,  the  coals 
improve  in  purity  down  the  river. 

As  an  offset  to  this  advantage  of  the  coals  from  the  lower  counties, 
the  coals  from  the  counties  higher  up  Des  Moines  river  contain  both 
a  greater  per  centage  of  coke  in  the  coal  and  a  greater  proportion 
of  carbon  in  the  combustible.  For  coking,  and  therefore  also  for 
smelting  purposes,  these  latter  are  thus  better  than  those  from  the 
lower  counties. 

To  express  this  difference  in  the  plainest  language,  I  might  say : 
The  coals  from  the  lower  counties  on  the  Des  Moines  river  are,  on 
the  whole,  more  bituminous,  more  baking,  burning  with  more  flame, 
leaving  less  ashes,  than  those  from  the  counties  higher  up  the  river; 
but  then  the  latter  give  more  coke,  and  a  more  intense  heat  than  the 
former. 

In  following  any  one  of  the  columns  downward,  it  will  be  noticed 
that  this  change  is  very  gradual  and  of  but  small  amount ;  on  the 
average,  only  four  per  cent  difference.  It  will  also  be  seen  that  the 
actually  determined  mean  for  the  State  is  very  nearly  as  stated  in 
round  numbers  in  the  second  article ;  the  only  deviation  being  two 
per  cent  greater  amount  of  moisture,  and  two  per  cent  smaller 

amount  of  bitumen. 
29 


226  KEPORT  OF  STATE  GEOLOGIST. 

It  must  be  borne  in  mind  that  the  values  here  referred  to  are 
means  for  counties,  and  the  fact  that  the  coals  from  Marion  county 
contain  ten  per  cent  of  ashes  must  not  be  understood  as  meaning 
that  all  coals  from  that  county  actually  contain  so  much ;  the  mean 
of  ten  per  cent  results  from  some  containing  more,  others  less,  than 
.this  amount. 

Again,  though  on  the  whole  the  per  centage  of  ashes  increases  in 
an  upward  direction  along  the  Des  Moines  river,  it  must  not  be 
understood  that  there  are  no  coals  in  the  lower  counties  with  more 
ashes,  no  coals  in  the  upper  with  less  ashes.  By  reference  to  the 
preceding  table  we  see  that  the  lower  part  of  Carmine's  bank  con- 
tains 8T3ff  per  cent  of  ashes,  (VanBuren  county),  while  the  sample 
from  Redhead's  mine  in  the  city  of  Des  Moines  only  contains  2T3¥  per 
cent  of  ashes. 

All  the  results  of  the  analyses  here  reported  have  been  represented 
on  a  map,  drawn  on  a  scale  of  four  miles  to  the  inch.  By  a  peculiar 
method,  all  particulars  of  any  coal  -  bank  are  represented  to  the  eye. 
The  publication  of  such  a  map  must  of  course  be  delayed  until  much 
more  material  has  become  available. 

In  conclusion  I  would  add  one  more  observation.  This  fourth 
article,  giving  the  results  of  my  analyses,  is  a  statement  of  facts ; 
any  one  who  doubts  it  has  all  means  of  satisfying  himself  by  having 
repeated  the  analysis  of  the  identical  specimen  now  in  the  cabinet 
of  the  State  University.  The  statement  in  regard  to  the  existence 
and  relative  position  of  the  two  coal  -  banks,  as  contained  in  the  third 
article,  is,  to  a  considerable  extent,  a  conclusion.  With  the  increase 
of  the  number  of  specimens  analyzed,  the  basis  of  that  conclusion 
may  change,  and  with  it  the  conclusion  itself  may  be  modified. 
Again,  there  is  a  possibility  that  two  banks  might  be  different, 
and  yet  be  identical  in  their  chemical  composition ;  at  any  rate,  the 
impossibility  of  such  a  condition  of  things  has  not  been  proved ;  but 
making  due  allowance  for  all  these  circumstances,  I  repeat  that  the 
tracing  of  the  two  coal  -  banks  along  the  Des  Moines  river  is  the  only 
one  yet  made  that  I  know  of;  and  although  both  the  novelty  of  this 
attempt  and  the  facilities  for  such  purpose,  limited  number  of  analy- 
ses, calls  for  further  chemical  and  geological  research. 


REPOKT  OF  STATE  GEOLOGIST.  227 

V.      THE   CHEMICAL   HISTORY   OF   COAL. 

The  great  economical  importance  of  coal,  the  peculiarities  of  the 
distribution  of  this  fuel  and  the  many  remarkable  physical  and 
chemical  characters  make  the  question  as  to  its  origin  not  only  one 
of  great  interest,  but  also  of  great  difficulty. 

Although  many  writers  on  geology  consider  the  complete  history 
elucidated,  and  with  great  assurance  give  detailed  accounts  of  the 
precise  mode  of  the  formation  of  coal,  many  eminent  authors  do  not 
hesitate  to  acknowledge,  that  hardly  any  thing  but  the  mere  vegetable 
origin  of  coal  is  demonstrated.  Mr.  Hunt,  states  the  case  with 
perfect  frankness  in  the  recent  supplement  to  lire's  Dictionary,  when 
he  says :  "  That  coal  is  derived  from  the  vegetable  kingdom,  no 
longer  admits  of  doubt;  but  the  class  of  plants  to  which  more 
especially  we  are  to  look  for  the  origin  of  coal,  is  still  a  matter  of 
much  uncertainty,  and  the  conditions  under  which  the  change  is 
brought  about  is  very  imperfectly  understood,  and  indeed,  by  many 
geologists  entirely  misconceived." 

The  greater  part  of  this  uncertainty  seems  to  be  due  to  the 
apparent  neglect  of  the  chemical  properties  of  the  coal.  Professor 
F.  Mohr  of  Bonn,  Germany,  has  lately  shown>  that  all  known  facts 
in  relation  to  coal  are  best  explained  by  considering  the  stone  -  coal 
as  a  result  of  the  carbonization  of  marine  plants,  algae,  and  that 
this  even  will  explain  a  great  number  of  well  ascertained  geological 
phenomena,  which  protest  against  the  generally  accepted  hypothesis 
that  coal  is  due  to  land  -  plants.  My  own  investigations  of  the  Iowa 
coal  have  contributed  very  much  to  the  conviction  I  now  hold,  that 
the  theory  of  Mohr  in  regard  to  the  formation  of  stone  -  coal  is  the 
true  one ;  at  any  rate,  the  theory  of  Mohr  does  not  solely  rest  upon 
the  nature  of  accidental  matters  ia  the  coal,  but  upon  a  careful 
investigation  of  the  body  of  the  coal  itself. 

Referring  to  the  first  article,  it  may  be  remembered  that  wood, 
peat  and  brown  coal  were  there  ascribed  to  land  -  plants,  coal,  to 
sea  -  plants.  In  order  to  prevent  a  possible  misunderstanding,  I  shall 
instead  of  coal,  use  the  word  stone  -  coal,  to  indicate  all  true  coals 
from  anthracite  to  our  bituminous  coal  of  Iowa. 

Forests  and  peat  -  bogs  grow  before  our  eyes ;  their  origin  is  well 


228  REPORT  OF  STATE  GEOLOGIST. 

known.  Brown  coal  has  in  its  mass  so  plainly  the  structure  of  laud- 
plants,  that  its  origin  is  not  questioned ;  besides,  we  here  in  the 
Mississippi  valley  know  that  we  are  in  the  very  coal  -  era,  for  the 
immense  amount  of  trees  brought  down  to  the  gulf  of  Mexico  from 
all  parts  of  this  great  valley,  is  now  forming  a  great  brown  coal 
deposit,  like  those  now  explored  on  the  Pacific  coast  of  this  country. 
Leaving  everything  of  a  purely  geological  nature  to  others,  I  shall 
confine  myself  to  the  consideration  of  the  stone  -  coal  as  a  substance 
which  could  neither  have  been  formed  from  trees,1  nor  from  peat 
bogs,  nor  from  brown  coal,  but  only  from  sea  -  weeds.  It  will  be  the 
simplest  to  consider  the  actual  contrast  between  the  properties  of 
wood,  peat  and  brown  coal,  being  the  products  of  woody  fibre  on  the 
one  hand,  and  the  properties  of  stone  -  coal,  which  we  stated  to  be 
produced  from  sea-  weeds,  on  the  other  hand. 

First. — If  wood  is  heated  in  a  closed  vessel,  so  that  the  air  can 
not  get  to  the  wood,  this  latter  will  never  fuse,  but  only  become 
charred.  All  are  familiar  with  the  fact,  that  charcoal  shows  even 
the  nicest  details  of  the  structure  of  the  wood  from  which  it  was 
made.  So,  also,  brown  coal,  and  peat,  never  fuse,  but  retain  their 
structure. 

But  most  true  stone  -  coals  do  fuse  under  these  circumstances  ;  all 
Iowa  coals  that  I,  as  yet,  have  analyzed,  did  fuse  ;  some  very  easily. 

That  this  marked  difference  depends  on  the  structure  of  the 
substance,  we  know  from  the  fact,  that  sugar  in  charring  does  fuse, 
while  woody  fibre  does  not ;  both  substances  have  precisely  the  same 
elementary  composition,  but  they  diifer  widely  in  regard  to 
structure. 

This  difference  between  stone  -  coal  and  the  other  fuels  is  contrary 
to  both  the  peat -bog  theory  and  the  wood  theory;  but  if  stone- 
coal  is  formed  of  sea -weeds,  this  property  is  a  necessity,  for  all 
sea -weeds  when  thus  treated,  fuse  very  readily. 

Another  difference  we  have,  is  the  fact  that  wood  continues  to 
burn  when  taken  from  the  flame  —  stone  -  coal  not ;  the  coals  from 
sea -weeds  act  in  this  respect  precisely  like  stone-coal. 

Second.  —  When  pulverized  brown  -  coal  or  peat  are  boiled  in 
pottassa  lye,  a  deep  brown,  almost  black,  solution  is  obtained;  when 


REPORT  OF  STATE  GEOLOGIST.  229 

stone-  coal  is  treated  in  the  same  way,  the  lye  remains  almost  color- 
less. This  coloring  matter  is  called  humus ;  it  is  also  found  in  our 
soils,  and  is  a  product  resulting  from  woody  fibre.  Since  stone  -  coal 
is  without  humus,  it  proves  itself  devoid  of  woody  fibre. 

Third.  —  Stone  -  coal  has  always  but  a  few  per  cent  of  moisture  ; 
brown  coal  and  peat  retain  a  very  great  amount  of  moisture  with 
pertinacity.  Thus,  in  the  Irish  peat  analyzed  by  me,  I  found  sixteen 
per  cent  of  moisture.  In  brown  coal  from  Bilin  also  sixteen ;  in 
stone  -  coal  from  Silesia,  only  five ;  cannel  coal  from  Wigan,  only 
three.  All  of  these  specimens  had  for  several  years  been  kept  in 
the  same  case  in  the  air  -  heated  labaratory,  so  that  they  represent 
these  fuels  as  thoroughly  and  equally  air  -  dry.  Now  this  is  quite 
general;  all  chemists  are  aware  of  this  radical  difference  between 
stone  -  coal  and  those  fuels  which  we  know  to  be  derived  from  woody 
fibre.  Hence,  again  the  conclusion  that  stone  -  coal  is  not  derived 
from  woody  fibre. 

Fourth.  —  When  stone-coal  is  subjected  to  dry  distillation  in  the 
retorts  of  the  gas  -  works  for  the  purpose  of  manufacturing  illumin- 
ating gas,  great  quantities  of  ammoniacal  liquid  is  obtained;  in  fact, 
almost  all  the  ammoniacal  salts  now  used  in  the  arts,  are  thus 
extracted  from  stone  -  coal. 

When  wood  is  subjected  to  the  same  treatment,  no  such  ammon- 
iacal liquid  is  obtained;  on  the  contrary,  instead  of  this  alkaline 
liquid,  an  acid  is  obtained,  called  wood  -  vinegar.  Peat  and  brown 
coal  treated  the  same  way,  likewise  give  an  acid  liquid. 

This  great  difference  forms  the  basis  of  Mohr's  theory,  here 
advocated ;  it  is  indeed  utterly  impossible  to  see  how  the  nitrogen 
necessary  to  form  the  ammonia  should  have  got  into  the  woody  fibre, 
if  they  were  the  source  of  stone  -  coal.  On  the  other  hand,  sea- 
weeds are  exceedingly  rich  in  nitrogen,  and  if  they  were  charred 
in  any  way,  much  nitrogen  would  remain. 

That  this  difference  between  stone-coal  and  the  other  fuels  is 
constant  and  general  has  been  proved  by  an  extensive  series  of 
experiments  performed  by  the  German  chemist,  Kremers. 

Fifth.  Near  the  sea -shore  we  always  find  the  smell  of  sulphu- 
retted hydrogen  more  or  less  perceptible ;  we  know  it  to  be  due  to 


230  REPORT  OF  STATE  GEOLOGIST. 

the  decay  of  sea-  weeds  thrown  on  the  shore.    Wood,  when  thus  rot- 
ting, does  not  emit  such  odor. 

The  amount  of  sulphur  in  the  coals  is  very  great ;  the  smell  near 
the  gas  -works  sufficiently  known  is  an  abundant  proof.  Brown  coal 
and  peat  do  not  contain  so  much  sulphur ;  the  iron  associated  with 
these  fuels  is  more  commonly  found  as  carbonate  or  oxide  than  as 
sulphuret. 

Sixth.  Sea -weeds  contain  constantly  considerable  iodine  and 
bromine  ;  land  -  plants  contain  rarely  any.  But  the  compound  of 
these  elements  is  mostly  soluble,  and  therefore  to  a  great  extent 
washed  out  of  the  coal  before  we  get  hold  of  it ;  still  several  chem- 
ists have  proved  the  presence  of  iodine  in  the  ashes  of  stone-coal, 
and  Mohr  has  lately  succeeded  in  finding  even  bromine  in  the  coal. 

That  finally  the  sea -weeds  are  a  sufficient  cause  for  the  produc- 
tion of  the  vast  coal-beds,  need  not  here  be  proved;  it  will  be 
enough  to  state  that  even  a  single  weed  often  measures  hundreds  of 
feet  in  length,  being  provided  with  branches  and  leaves  of  corre- 
sponding magnitude ;  that  these  weeds  abound  in  all  seas  ;  that  they 
necessarily  sink  to  the  bottom  when  they  die,  and  thus  decaying 
under  water,  must  form  a  carbonaceous  mass  ;  that  finally  peat  -  bogs 
are  small  as  compared  to  large  forest  regions,  and  that  again  these 
are  insignificant  when  compared  to  the  vast  fields  of  sea  -  weeds  well 
known  to  mariners — fields  of  truly  continental  magnitude?  While 
on  the  soil  only  a  limited  amount  of  combustible  can  be  accumulated, 
there  is  no  limit  to  this  accumulation  in  the  deep. 

While  thus  the  chemical  nature  of  stone  -  coal  proves  that  it  never 
could  have  resulted  from  vascular  plants  or  land  plants,  that  is, 
plants  essentially  made  up  of  woody  fibre,  and  furthermore,  that 
the  chemical  nature  of  stone-coal  exactly  harmonizes  with  that 
resulting  from  sea -weeds;  while  further,  no  land  vegetation  is  ade- 
quate to  account  for  the  thickness  and  the  extent  of  the  stone  -  coal 
fields  of  the  world,  and  particularly  for  those  of  the  Mississipi 
Valley,  requiring  a  vegetation  as  immense,  as  uniform  and  persis- 
tent as  that  of  the  sea  -  weeds  of  the  ocean ;  while  considering  all 
this  we  have  purposely  omitted  to  refer  to  the  uniformity  in  the 
strata,  the  regular  interposition  of  marine  rocks  among  the  coal- 
beds,  the  accompanying  fossils,  etc.  On  these  grounds  Mohr's  theory 


REPORT  OP  STATE  GEOLOGIST.  231 

is  also  infinitely  superior  to  the  commonly  accepted  one ;  for  not  all 
thinkers  are  ready  to  clothe  the  earth  with  a  more  luxuriant  growth 
than  now  is  observed ;  nor  have  we  a  ready  command  over  the 
creeping  centuries ;  nor  have  we  ever  seen  vegetable  debris  piled 
up  in  sufficient  quantity  to  form  a  coal  -  bed.  Geologists  are  taking 
a  little  more  care  of  the  crust  of  the  earth  of  late  ;  they  are  not 
quite  so  ready  now,  as  formerly,  to  assume  that  a  vast  region  of  land 
emerged  about  a  hundred  times  out  of  the  ocean,  and  sank  again. 

The  very  water  in  the  sea,  in  the  constitution  of  the  air  it  con- 
tains, gave  Mohr  a  convincing  proof  of  the  continuous  formation  of 
coal  at  the  bottom  of  the  ocean,  even  in  our  day. 

In  the  preceding  I  have  given  a  short  synopsis  of  some  points  of 
Mohr's  theory  of  the  formation  of  coal ;  it  rests  throughout  upon 
well  -  recognized  facts,  does  not  require  nature  to  work  otherwise 
than  as  we  now  observe  her  working,  and  instead  of  ignoring  the 
chemical  nature  of  the  coal  whose  origin  we  wish  to  discover,  it  actu- 
ally made  the  investigation  of  this  constitution  the  starting-point. 

For  Iowa,  this  theory  has  a  very  great  importance ;  for  if  the  older 
theories  are  true,  then  we  need  hardly  expect  coal  underlying  the 
rocks  in  the  more  central  parts  of  the  basin ;  but  if  Mohr's  theory 
is  true,  then  the  coal  will  extend  over  the  whole  of  this  field.  For 
this  reason  —  and  also  because  this  theory  seems  hardly  yet  known 
in  America  —  I  have  deemed  it  not  improper  to  give  a  short  synopsis 
of  the  same. 

My  own  investigation  of  the  Iowa  coals  has  added  four  more  not 
unimportant  proofs  to  the  theory  in  four  facts  which  can  not  possibly 
be  accounted  for  by  the  old  fanciful  views. 

The  first  of  these  facts  is  the  great  uniformity  in  the  composition 
of  a  coal  -  bank  over  quite  a  considerable  area. 

The  second  is  the  fact  that  the  upper  parts  of  our  Iowa  coal  -  banks 
contains  the  most  pyrites ;  the  lower  parts  being  very  often  entirely 
free  from  this  substance.  The  sulphuretted  hydrogen  set  free  in  the 
carbonizing  sea -weeds  escapes  upward;  in  meeting  the  ferruginous 
waters,  pyrites  would  result,  so  that  these  latter  would  predominate 
in  the  upper  parts  of  the  resulting  coal-bed. 

The  third  consists  in  the  investigation  of  the  fibrous  portions  often 
met  with  in  our  Iowa  coals.  These  portions  look  and  feel  precisely 


232  REPORT  OF  STATE  GEOLOGIST. 

like  charcoal ;  retain  a  distinct  fibrous  structure.  By  analysis  of  the 
same  I  found  them  to  contain  but  very  little  of  bitumen,  as  compared 
to  the  closely  adjoining  coal ;  and  saw,  that  even  after  protracted 
exposure  to  white  heat,  they  retained  their  structure ;  indeed,  the 
coked  mass  looked  precisely  as  the  fibres  did  before  coking,  while 
the  coal,  wherein  they  were  imbedded,  was  highly  baking. 

This  shows  plainly  that  the  woody  fibre  irregularly  distributed  in 
small  portions  through  some  of  our  Iowa  coals  never  lost  its  peculiar 
structure,  but  merely  was  charred ;  that  the  entirely  different  sub- 
stance forming  the  bulk  of  our  coal,  therefore  originally  also  must 
have  been  entirely  different  from  these  fibrous  plants.  Of  quite  par- 
ticular interest  is  the  fact,  that  while  this  fibrous  coal  upon  drying 
deported  itself  like  other  vascular  fuels,  (wood,  etc.,)  the  mass  all 
around  it  increased  in  weight,  as  I  shall  now  explain. 

Fourth.  By  very  careful  working  I  discovered  that  all  our  Iowa 
coals,  after  having  lost  their  moisture,  commenced  upon  further  dry- 
ing at  a  temperature  a  little  above  that  of  boiling  water,  to  increase 
in  weight,  an  increase  sometimes  amounting  to  fully  two  or  more  per 
cent.  Prof.  Whitney  had  noticed  this  in  some  cases ;  in  another 
place  I  have  shown  how  he  came  to  miss  the  general  law.  This  same- 
property  I  have  also  discovered  in  cannel  coal  from  England,  and 
stone  -  coal  from  Silesia,  so  that  I  consider  it  a  property  common  to 
all  stone  -  coals.  Neither  peat,  nor  brown  coal,  nor  bituminous  wood, 
did  as  yet  show  this  peculiar  increase  in  weight ;  so  that  this 
property  must  be  considered  a  new  distinctive  property  peculiar  to 
stone-coal.  It  forms  therefore  an  additional  impossibility  concern- 
ing the  old  theories  of  coal,  and  a  new  link  in  the  chain  of  facts  on 
which  the  chemical  theory  of  Mohr  rests. 

Coal,  true  stone  -  coal,  was  not  restricted  to  a  particular  period  in 
the  earth's  history,  but  it  is  forming  even  at  the  present  day  in  the 
oceans. 


CHEMICAL  REPORT  ON  THE  WATER  AND  ROCKS  OF  THE  STATE, 


CHAPTER    II. 

I.      THE   WATER. 

We  are  very  apt  to  consider  the  rocks  as  permanent,  and  yet  they 
are  continually  changing.  The  principal  cause  of  this  change  is  the 
moving  water  in  the  rocks.  When  it  slowly  washes  solid  matter  out 
of  the  rocky  strata,  the  land  may  be  gradually  sinking  and  more 
sudden  changes  felt  over  a  large  extent  of  territory  as  an  earth- 
quake, may  follow;  we  might  here  refer  to  the  earthquake  which  was 
felt  sometime  last  spring,  over  a  great  portion  of  the  Northwest, 
after  a  particularly  wet  season. 

To  understand  the  change  of  the  rocks  and  to  investigate  their 
original  formation  it,  therefore,  is  necessary  to  carefully  analyze  the 
waters  they  contain.  The  more  direct  demand  of  people  possessing 
mineral  springs,  thus  meets  a  scientific  necessity,  in  requiring  careful 
analyses  of  the  waters  of  the  State. 

During  the  former  geological  survey  no  waters  were  analyzed. 
My  proximate  analyses  of  the  water  of  the  artesian  well  at  Mt. 
Pleasant  (summer  1865)  together  with  an  accurate  analyses  of  the 
water  of  a  spring  near  the  same  place,  made  by  me  at  the  order  of 
Dr.  Mark  Ranney  early  in  1866  were  the  only  two  analyses  of  Iowa 
waters  executed  previous  to  the  present  survey. 

The  most  important  of  the  waters  yet  analyzed  is  that  of  the 
artesian  well  at  Mt.  Pleasant,  on  the  ground  of  the  Iowa  Hospital 
for  the  Insane.  The  State  Geologist  procured  about  six  gallons  of 
the  water  in  order  to  enable  me  to  make  a  complete  analysis  of  the 
same.  Of  this  water  I  have  used  two  gallons  this  fall  to  determine 
the  proportion  of  these  substances  which  are  present  in  considerable 
quantities.  The  remaining  water  will  be  used  in  order  to  determine 
30 


234 


REPORT  OF  STATE  GEOLOGIST. 


those  substances  which  are  present  in  very  small  quantities.  In  the 
bottles  I  noticed  a  very  fine  crystalization  of  dolomite.  This  fact  is 
of  considerable  importance,  as  it  shows  that  such  waters,  by  perco- 
lating the  limestone,  may  gradually  change  them  altogether  into 
dolomities.  For  the  sake  of  comparison  I  take  the  liberty  to  make 
use  of  the  analysis  of  the  Mt.  Pleasant  spring  water,  although  this 
analysis  is  not  the  property  of  the  survey. 

LOCALITIES   OF   THE   WATERS. 

The  waters  analyzed  as  yet  were  nearly  all  from  the  First  Con- 
gressional District.  They  are  in  the  mineralogical  collection  of  the 
survey,  designated  by  the  following  numbers  inscribed  on  the  labels : 

No.  24.  Mineral  spring,  on  S.  D.  Well's  farm,  on  section  fifteen, 
township  seventy,  range  thirteen,  near  Bloomfield,  Davis  county. 

No.  72.  Salt  spring,  from  the  largest  salt  spring  at  the  crossing 
of  Salt  creek  and  the  Bloomfield  road,  in  the  northeast  portion  of 
Davis  county. 

No.  114.  Artesian  well,  Mt.  Pleasant,  Henry  county ;  depth  of 
boring,  1,125  feet ;  temperature  of  the  water  (November  6,  1866,) 
62°  F.,  while  the  common  well  showed  only  55°  F. — [WHITE.] 

No.  120.  Water  from  the  Ottumwa  school  well,  sent  by  Dr. 
Warden. 

No.  460.  Well  on  Kinersly's  farm,  one  mile  from  Keosauqua, 
Van  Buren  county. 

The  total  amount  of  mineral  matter  in  these  waters  is  very  differ- 
ent. In  order  the  better  to  understand  these  relations,  I  add  a  few 
determinations  of  other  waters.  All  figures  refer  to  10,000  parts  of 
water : 


NO.                                               WATER. 

SALTS. 

BY  WHOM  ANALYZED. 

'460 

24 
114 

72 
120 

Croton  W8itcr  New  York 

1.0 

3.5 
10.9 
24.4 
25.3 
29.7 
39.5 

49.6 
344 
2500 

Silliman        .  .       ... 

IOWA  WATERS. 

Spring  water    Mt  Pleasant 

Hinrichs 

Kinersly's  W6ll    "Va/o  Bur6n  county     

Hinrichs     

Wells'  spring  Davis  county               

Hinrichs  

Artesian  well    Mt  Pleasant 

Hinrichs                .    .  . 

Salt  spring  Davis  county                    .     .  .     . 

Hinrichs  

School  well    Ottumwa       

Hinrichs  

OTHER  WATERS. 

Congress  spring  Saratoga  N  Y       

Schweitzer  

Ocean  (mean  of  several  hundred  analyses)  
Salt  well,  Luneberg,  Prussia  

Forchhammer 

Forchhammer  

REPORT  OF  STATE  GEOLOGIST.  235 

This  latter  is  one  of  the  most  nearly  saturated  brines  known.  It 
is  evident  that  salt  spring  No.  72  is  exceedingly  sweet  as  compared 
to  the  Luneburg  well.  One  of  the  poorest  brines  used  is  that  of 
Salzhausen,  Germany,  containing  about  120  parts  of  salts  to  10,000 
water,  or  about  four  times  as  much  as  our  salt  spring;  and  even  the 
former  brine  is  only  worked  by  making  use  of  the  refuse  coal  from 
a  coal  mine  at  the  same  place.  In  the  United  States,  salt  is  too 
abundant  that  such  wells  could  be  utilized. 

NATURE   OF   THE   MINERAL  MATTER. 

In  the  salt  spring  (No.  72)  and  well  spring  (No.  24),  common  salt 
dominates  over  the  other  mineral  ingredients ;  yet  both  waters  con- 
tain a  considerable  amount  of  sulphuric  acid.  In  the  Ottumwa  well 
(No.  120)  and  Kinersly's  (No.  460),  iron  abounds ;  they  are  almost 
vitriolic  waters,  and  altogether  unfit  for  use.  The  mineral  matter 
of  the  Ottumwa  well  was  found  to  consist  of  — 

Ferruginous  sediment  in  the  bottle 10.2 

Gypsum 10.4 

Ferric  sulphate,  common  salt,  etc 18  9 

Total  in  10,000  water 39.5 

The  spring  at  Mt.  Pleasant  contains  principally  calcium  carbonate 
(65  per  cent  of  all  salts) ;  the  artesian  well  water  is  characterized 
by  the  predominance  of  sulphates ;  (84  per  cent  of  all  its  salts  are 
sulphates).  These  two  waters  having  been  accurately  analyzed,  it 
may  be  interesting  to  report  the  final  result,  showing  the  various 
mineral  ingredients  for  100,000  parts  of  water. 

ARTESIAN  WELL  AND  SPRING -WATER,  MT.  PLEASANT. 

The  mineral  constituents  of  waters  are  given  first :  the  elements 
separately ;  second,  these  combined  to  bases  and  acids ;  third,  the 
same  estimated  as  salts.  Now,  neither  the  second  nor  the  third 
method  is  quite  exact,  since  we  do  not  positively  know  how  the 
elements  really  are  combined ;  so  that  the  first  mode  of  stating  the 
results  seems  to  be  the  safest.  Nevertheless,  it  has  hardly  come 
into  use,  and  for  some  practical  applications  the  third  statement  is 
the  most  convenient. 


236 


REPORT  OF  STATE  GEOLOGIST. 


IN  TEN  THOUSAND  WATER. 


ELEMENTS. 


(SPRING.  |ART.  WELL.  RATIO. 


I.   METALS. 

Sodium                             ... 

0013 

4  585 

352 

Magnesium  ...         

0063 

0.630 

1.7 

Calcium  -  

0900 

2.750 

3.0 

II.   NON-METALIC  ELEMENTS. 

Sulphur         

0028 

4876 

174 

Carbon  

0409 

3.305 

076 

Chlorine                                            . 

0020 

1  200 

60 

Oxygen 

1  735 

10974 

63 

Total 

347 

2532 

73 

Sediment  in  flask.. 

0.40 

The  *ratio  in  the  last  column  is  obtained  by  dividing  the  figures 
under  artesian  well  by  those  under  spring;  or  the -ratio  expresses 
how  many  times  the  water  of  the  artesian  well  contains  the  amount 
of  the  elements  in  the  spring  water.  If  the  elements  were  present 
in  both  of  these  waters  in  the  same  proportion,  then  7.3,  the  ratio 
of  the  totals,  would  be  the  ratio  for  the  several  elements  also.  In 
fact,  only  the  ratio  for  oxygen  approaches  to  this  ratio;  all  others 
differ  very  much  from  7.3,  &c.  The  ratio  for  sodium,  sulphur  and 
chlorine  are  particularly  great ;  or  in  words,  the  water  from  the  deep 
(artesian)  well  contains  proportionally  much  more  of  sodium,  sulphur 
and  chlorine,  than  the  water  from  near  the  surface  (spring).  The 
two  waters,  both  from  the  same  place,  but  from  very  different 
depths,  therefore  differ  very  much,  not  only  in  the  total  amount  of 
mineral  matter,  but  even  more  so  in  regard  to  the  quality  of  the 
same. 

IN  TEN   THOUSAND   OF  WATER. 


SECOND  —  Binaries. 

SPRING 

ART. 
WELL. 

0.33 

1.97 

0.07 

12.19 

Carbolic  acid     

1.50 

1.12 

1.26 

3.85 

0.605 

1.05 

Soda  

5.14 

THIRD — Salts. 


Sodium  chloride  (common  salt)     

0.33 

1.97 

11.77 

Magnesium  sulphate  (epsom  salt)      

0.21 

3.15 

5.86 

Calcium  carbonate  (ralcite)                         .     

2.250 

2.55 

Magnesium  carbonate  (magnesia  alba)  

(1.975 

REPORT  OF  STATE  GEOLOGIST.  237 

The  names  in  parenthesis  are  added  for  those  of  the  readers  who 
may  not  be  familiar  with  the  names  of  the  salts. 

The  amount  of  salts  even  in  the  artesian  well  may  appear  insig- 
nificant —  only  about  one  -  fourth  of  one  per  cent !  But  when  larger 
quantities  of  the  waters  are  used,  then  these  salts  become  plainly 
manifest  to  everybody.  The  steam  -  engine  at  the  Iowa  Hospital  for 
the  Insane  is  reported  to  have  pumped  the  water  for  use  at  the  rate 
of  ten  thousand  gallons  an  hour.  This  is  more  than  eighty  thousand 
pounds  an  hour,  and  the  insignificant  amount  of  salts  is  more  than 
two  hundred  pounds  per  hour  !  At  that  rate  the  following  pounds  of 
the  different  salts  would  be  brought  up  with  the  water  each  hour  : 

Lbs. 

Common  salt ,   16 

Glauber  salt 94 

Epsom  salt 25 

Gypsum  and  calcium  carbonate •. .  67 

Or  these  salts  would  contain  of 

Sulphur 39 

Carbon 3 

Chlorine  gas , 10 

Magnesium  metal 5 

Calcium  metal 22 

Sodium  metal 37 

111  the  course  of  ten  hours  these  salts  would  amount  to  a  ton  ! 
Only  a  small  amount  of  these  used  in  a  boiler  would  quickly  produce 
a  thick  incrustation  ;  the  sulphates  would  remain  pretty  long  in  solu- 
tion, so  that  a  pretty  concentrated  brine  might  result  —  all  of  which 
has  been  so  abundantly  experienced  that  the  water  is  no  longer  used 
for  such  purposes.  In  the  proximate  analysis  of  1865  the  chlorine 
was  not  determined.  By  my  recent  careful  and  complete  analysis 
recorded  above,  it  is  seen  that  there  is  plenty  of  chlorine,  which,  in 
the  presence  of  sulphuric  acid  and  some  free  carbonic  acid,  may  set 
free  the  corroding  vapors  of  hydrochloric  acid. 

I  intend  to  subject  this  water  to  still  more  scrutinizing  analyses  ; 
then,  together  with  the  investigations  of  the  specimen  rock  from  the 
boring,  the  boiler  deposits,  the  corroded  iron  tubes,  and  the  surface' 
water  from  the  same  place  will  form  a  whole  of  well  ascertained  facts 
for  various  levels  from  the  surface  to  a  depth  of  one  thousand  one 


238  REPORT  OF  STATE  GEOLOGIST. 

hundred  and  twenty  -  five  feet,  which  I  hope  will  lead  to  some  general 
results. 

One  very  interesting  general  result  may  already  here  be  pointed 
out.  If  we  calculate  the  per  centage  of  the  various  salts  in  the  two 
waters,  we  find : 


Q  A  T  T»q 

PER  C 

ENTAGE. 

Spring. 

Art'n  Well. 

Sodium   sulphate            ....     .       .      .  . 

0 

46 

Sodium  chloride  

1 

6 

6 

12 

Calcium   sulphate                                           .       .       , 

28 

26 

Calcium   carbonate.. 

65 

10 

This  shows  a  marked  decrease  in  the  proportion  of  the  lime  salts, 
while  the  magnesium  salts,  and  particularly  the  alkali,  increase  as  we 
descend  below  the  surface.  The  surface  -water  is  a  calcareous  car- 
bonated water :  the  water  from  the  deep  is  sulphated  and  alkali- 
water.  The  latter  are  by  far  the  most  soluble  of  these  salts ;  and 
this  circumstance  causes  their  accumulation  in  the  deeper  waters. 
Quite  a  similar  change  our  surface  waters  undergo  in  their  course 
toward  the  ocean.  In  the  rivers  there  is  but  a  small  amount  of 
mineral  matter,  and  the  carbonates  of  lime  and  magnesia  dominate  ; 
both  become  less  and  less,  both  being  deposited  on  the  way  to  the 
ocean,  which,  like  the  water  from  the  deep  well  at  Mount  Pleasant, 
only  contains  the  most  soluble  salts.  The  more  immediate  cause  of 
this  change  in  the  rivers  is  the  life  of  aquatic  animals  ;  in  the  rocks 
the  same  change  is  brought  about  by  the  constant  metamorphosis  of 
the  rock  itself. 

The  preceding  contains  all  the  results  ascertained  in  regard  to  the 
waters  of  the  State.  Compared  with  what  remains  to  be  done,  it  is 
very  little;  but  compared  with  what  had  been  done  previously  it  is  a 
good  deal.  So  much  is  certain,  a  correct  interpretation  of  the  con- 
stitution of  the  rocky  framework  of  the  State  can  only  be  obtained  by 
a  careful  chemicaL  study  of  both  the  rocks  and  the  waters  they 
contain. 

II.      THE    ROCKS. 

The  rocks  of  Iowa  belong  to  only  four  kinds;  they  are  either 
calcareous,  arenaceous,  argillaceous,  or  carbonaceous.  To  the  first 


REPORT  OF  STATE  GEOLOGIST.  239 

belong  limestones  and  dolomites,  both  effervescing  (at  least)  with  hot 
acids.  They  greatly  dominate  in  the  State.  The  finest  arenaceous 
rock  of  Iowa  is  the  St.  Peter's  sandstone,  exposed  in  the  northeast- 
ern corner  of  the  State  ;  good  sandstones  are  also  found  in  the  coal- 
measures  of  Southern  Iowa,  and  finely  crystalized  silicia,  that  is, 
quartz,  abounds  in  the  geodes  found  near  Keokuk  and  other  places. 
Shales  are  the  most  common  representatives  of  the  argillaceous 
rocks,  passing  by  the  dark,  more  or  less  combustible  varieties  gradu- 
ally into  coal)  the  most  valuable  carbonaceous  rock  of  Iowa.  Geo- 
logically, coal  is  as  much  rock  as  the  limestone  underlying  the  same, 
or  the  sandstone  above  it ;  it  is  found  stratified  like  either  of  these 
two  rocks. 

These  four  kinds  of  rock  are  composed  of  but  six  different  chem- 
ical elements.  Three  of  these  are  metals,  having,  when  pure,  a 
lustre  peculiar  to  these  bodies  ;  the  other  three  are  metalloids,  being 
devoid  of  such  lustre.  The  three  metals  are  calcium,  magnesium 
and  aluminum,  of  which  the  last  two  are  already  quite  frequently 
used  in  the  arts ;  magnesium,  the  metal  contained  in  epsom  salts, 
being  used  for  illuminating  purposes,  since  it  gives  a  most  dazzling 
light ;  aluminum,  the  metal  of  clay,  remarkable  for  its  beautiful 
silver  -  like  appearance  and  its  excessive  lightness,  being  not  heavier 
than  paper,  is  considerably  used  for  certain  alloys.  Calcium  has  as 
yet  not  found  any  application  in  the  arts.  About  forty  pounds  in 
every  hundred  pounds  of  pure  limestone  is  calcium. 

The  three  metalloids  are  oxygen,  carbon  and  silicon.  The  first 
constitutes  about  one  -  fifth  of  the  air  we  breathe,  and  is  really  the 
vital  principle  of  the  air ;  in  our  rocks  it  is  present  in  much  greater 
quantity  than  in  the  air,  for  it  constitutes  about  one  -  half  of  all  of 
them  (excepting  coal).  The  second,  carbon,  is  well  known;  in  char- 
coal we  have  it  nearly  pure.  Silicon  is  very  closely  allied  to  the 
former,  sand  being  composed  of  silicon  and  oxygen  in  nearly  equal 
proportions. 

The  following  table  will  give  a  correct  idea  of  the  elementary 
composition  of  our  Iowa  rocks,  by  means  of  the  per  centage  compo- 
sition of  the  purest  of  each  kind.  The  first  three  are  very  frequently 
met  with  almost  chemically  pure  in  crevices  and  openings  in  the 
rocks,  constituting  crystals.  In  limestone  we  thus  find  calcite  or 


240 


REPORT  OF  STATE  GEOLOGIST. 


calcium  carbonate  in  beautiful  crystals.  If  the  limestone  contains 
also  the  metal  magnesium,  we  usually  find  the  crystals  to  have  a 
peculiarly  pearly  lustre,  and  somewhat  curved  faces ;  these  crystals 
are  called  dolomite.  In  arenaceous  rocks  we  find  under  similar 
circumstances  the  beautiful  crystals  of  quartz.  The  other  two  rocks 
hardly  ever  occur  quite  so  pure  as  here  given,  except  it  be  carbon  as 
diamond.  These  pure  forms  are  the  minerals  corresponding  to  the 
rock ;  they  are  the  rock  purified  by  nature  herself : 


ROCK  AND  CORRESPONDING  MINERAL. 

ELEMENTS. 

METALOIDS. 

METALS. 

£3 

bfl 

0 

Carbon. 

Silicon. 

Calcium. 

Magnesium. 

Aluminum. 

CALCAREOUS  ROCKS. 

Calcile  

48. 
'52.2 

533 

12. 
13. 

467 

40. 
21.8 

13. 

.... 

Dolomite  ... 

ARENACEOUS  ROCK. 

ARGILLACEOUS  ROCK. 

Clay,  pure  

CARBONACEOUS  ROCK. 

Carbon,  nure.  . 

50. 

100 

25. 

.... 

25. 

In  dolomite,  which  in  the  north  of  the  State  forms  immense  fields 
contains  one  -  fifth  by  weight  of  the  metal  magnesium ;  if  this  is 
.separated,  it  burns  with  great  splendor.  We  may  now  readily  con- 
ceive what  an  immense  amount  of  heat  and  light  has  some  time  been 
produced  when  those  elements,  that  are  now  dormant  and  under  our 
feet,  were  still  uncombined  in  the  atmosphere,  perhaps.  Tolerably 
pure  limestone  contains  twelve  per  cent,  dolomite  about  thirteen  per 
cent  of  pure  coal ;  every  hundred  feet  of  limestone  contains  enough 
of  pure  coal  to  form  a  bank  of  anthracite  of  ten  to  twelve  feet  in 
thickness.  But  all  of  this  combustible,  both  metalic  and  carbon- 
aceous, is  now  unavailable,  since  these  elements  are  in  the  rock, 
combined  with  oxygen ;  that  is  they  are  burnt.  The  only  exception 
to  this  rule  is  the  coal ;  for  this  reason  it  has  so  great  economic 
value. 

The  coal  having  been  at  length  considered  in  the  first  chapter,  I 


REPORT  OF  STATE  GEOLOGIST.  241 

may  here  limit  myself  to  the  calcareous  rocks  of  the  State.     Neither 
the  arenaceous  nor  the  argillaceous  rocks  have  as  yet  been  analyzed. 

THE  CALCAREOUS  ROCKS  OF  IOWA. 

The  results  of  chemical  analysis  of  these  rocks,  are  usually 
stated  by  the  per  centage  of  each  of  the  proximate  chemical  com- 
pounds contained  in  the  same.  But  it  is  impossible  even  for  an 
expert  to  get  a  really  precise  idea  of  the  constitution  of  such  a  rock 
by  the  full,  unreduced  result  of  the  analysis.  It  is  as  difficult  as  to 
obtain  an  idea  of  the  value  of  a  sum  of  money  consisting  of  all  the 
various  coins  of  quite  a  number  of  nations.  This  will  become  much 
easier  by  referring  these  various  coins  of  each  nation  to  one  unit  as 
a  standard. 

Now,  this  is  what  I  have  done  for  the  analysis  of  Iowa  rocks, 
made  by  Professor  Whitney  during  the  former  survey ;  and  in  the 
same  way  I  give  the  final  result  of  my  own  analysis  of  the  rocks. 
I  refer  the  composition  to  the  per  centage  of  the  mineral  species 
which  undoubtedly  make  up  the  rock.  The  preceding  was  intended 
to  convey  a  definite  idea  of  what  the  species  are  for  our  State ;  and 
as  the  non- calcareous  rocks  also  are  insoluble,  we  unite  under  the 
heading  insoluble  the  arenaceous  and  argillaceous  part  of  the  rocks 
under  one.  Whenever  some  other  matters,  like  moisture,  soluble 
iron  compounds,  or  alkalies  are  determined,  I  sum  these  up  under 
the  heading  "  others."  The  character  of  the  rock  thus  is  always 
essentially  given  by  only  three  figures,  viz. :  the  per  centage  of  the 
insoluble,  of  the  calcite,  and  of  the  dolomite  in  the  same;  the 
"  others  "  spoken  of  are  only  present  in  small  proportions. 

As  an  example,  I  give  my  reduction  of  two  of  Whitney's  analyses : 

LOCALITY.  |Ualcite.|Dolomite.|lDSoluble.[Other8. 

Le  Claire,  bcott  County ' I      3.69  I      88.69     I      6/70      |    0.80 

Rock  Island,  Illinois I    98.551        0.58     |      0.42      | 


These  two  localities  are  only  about  twelve  miles  distant ;  the  above 
statement  shows  at  a  glance,  that  the  rock  at  LeClaire  approaches  to 
a  pure  dolomite,  while  at  Rock  Island  it  is  still  nearer  a  pure  calcite 
(carbonate  of  lime,  or  calcium  carbonate). 
31 


242  REPORT  OF  STATE  GEOLOGIST. 

In  order  to  show  the  advantage  of  this  form  over  the  one  com- 
monly used,  I  transcribe  Prof.  Whitney's  statement  from  the  report, 
for  the  Le  Claire  rock  : 

Silica  and  insoluble  silicates 6.70 

Peroxid  of  iron  and  a  little  protoxide 0.80 

Lime 29.06 

Magnesia 19.32 

Soda * 0.11 

SULPHURIC  ACID  AND  CHLORINE  —  MINUTE  TRACES. 

Carbonic  acid 43.65 

Loss 0.46 

This  is  the  direct  result  of  analysis  ;  it  is  the  grain  in  the  ear,  and 
in  order  to  become  digestible,  I  have  subjected  it  to  a  little  grinding, 
which  reduced  the  complicated  statement  to  but  three  essential 
figures,  viz : 

Per  cent. 

Calcite 3.69 

Dolomite 88.69 

Not  calcareous 7.50 

If  the  reader  only  will  take  the  trouble  to  get  a  clear  idea  of  the 
terms  calcite  and  dolomite  —  which  I  trust  may  be  obtained  from  the 
introductory  lines  —  the  constitution  of  the  calcareous  rocks  of  Iowa 
will  become  intelligible. 

The  geologist  represents  the  result  of  his  exploration  of  a  given 
field  by  sections,  showing  the  succession  and  super -position  of  the 
various  beds  of  rock.  These  sections  are  either  horizontal,  showing 
the  surface  -  formations  in  a  given  direction,  or  they  are  vertical,  rep- 
resenting the  order  and  thickness  of  the  rocks  one  above  the  other. 

It  is  evident  that  not  until  we  are  able  to  give  a  sufficient  number 
of  chemical  sections,  both  horizontal  in  all  directions  throughout  the 
State,  and  also  vertical  sections  of  a  considerable  and  well  -  selected 
number  of  localities,  not  until  then  can  it  be  said  that  we  really  know 
the  nature  of  the  rocks  of  the  State.  It  is  upon  the  chemical  con- 
stitution of  the  rock  that  the  practical  application  of  the  same  for 
the  various  purposes  depends ;  it  is  by  the  chemical  composition  that 
the  mineral  riches  of  the  rocks  are  influenced ;  and  it  is  the  chemical 
composition  of  the  rocka  which  determine,  to  a  great  extent,  the 
nature  of  the  soil  resting  on  top  of  it. 


REPORT  OF  STATE  GEOLOGIST. 


243 


It  is  impossible  to  represent  such  chemical  sections  without  proper 
wood  cuts.  In  the  absence  of  these,  the  numbers  from  which  such 
sections  are  drawn  will  here  be  given  in  a  few  tables. 

In  the  following  tabular  sections  I  insert  between  each  two  sam- 
ples the  distance  in  miles  between  the  places  where  the  rock  was 
taken;  these  distances  are  evidently  much  too  great,  showing 
that  a  great  many  more  analyses  will  have  to  be  made  before  the 
rocks  of  the  State  can  be  said  to  be  tolerably  well  known : 

MISSISSIPPI   SECTION. 

RESULTS  CALCULATED  FROM  WHITNEY'S  ANALYSES. 


PLACE. 


COUNTY. 


DISTANCE.    CALCITE.    DOLOMITE.    INSOL.    OTHERS. 


McGregor         friver 

L<lay  ton, 

37  miles 

063 

9841 

096 

Dubuoue  150ft  above 

Dubuque 

21  miles    . 

ox  Mag 

9559 

246 

Hickorv  Grov6 

Jackson    . 

44  miles    . 

224 

9783 

0.90 

Le  Claire  
Business  Corner 

Scott  
Van  Burcn 

12  miles    . 
90  miles 

3.69 

9087 

88.69 
418 

6.70 
057 

080 

Rook  Island   . 

Illinois..  . 

9855 

0.58 

0.42 

The  calcareous  rocks  along  the  Mississippi  are  therefore  nearly 
pure  dolomite  above  Rock  Island,  and  nearly  pure  limestone  below 
this  place.  That  such  is  the  case,  is  not  new,  but  no  previous  state- 
ment of  these  analyses  enabled  people  not  instructed  in  the  secrets 
of  chemical  analyses  to  see  it  so  plainly  as  the  above  figures  show  it. 

If  we  disregard  the  insoluble  part  of  the  rock,  then  we  may 
express  the  ratio  between  the  amount  of  dolomite  and  calcite,  by  one 
figure  alone ;  the  above  section  then  becomes  : 


PLACE.                                                                     COUNTY. 

RATIO. 

Clayton  ,  . 
Jackson.  .  . 
Scott    .... 

156.00 
43.00 
24.00 
0.006 
0.04 

LiG  Claire                                                                            .             . 

Illinois  .  ,  . 
Van  Buren 

Business  Corner  

Showing  in  a  still  more  simple  and  more  precise  form  the  remark- 
able fact  of  the  diminution  of  dolomite  towards  the  south.  In  Clay- 
ton county  the  rocks  contain  156  parts  of  dolomite  to  one  of  calcite; 
in  Jackson  only  43';  in  Le  Claire  only  24 ;  below  this  but  a  few,  or 
even  a  fraction  of  one  per  cent  of  dolomite.  This  gradual  decrease 
of  the  magnesian  ingredient  (dolomite)  in  the  rock  has  not  before 
been  made  so  perspicuous  as  by  this  ratio  : 


244 


REPORT  OF  STATE  GEOLOGIST. 


CEDAR  RIVER  SECTION. 
RESULTS  CALCULATED    FROM   WHITNEY'S   ANALYSES. 


| 

o5 

PLACE. 

COUNTY. 

DISTANCE. 

.2 

2 
'o 

M 

0 

"o 

£ 

& 

O 

o 
Q 

a 

O 

Shell  Rock  Falls.  .  . 

Cerro  Gorcio    .  .  . 

80  miles  

3.0  24.50 

73.60 

080 

1.10 

Indopendence 

Buchanan 

100  miles.  .  .  . 

002 

9711 

1  82 

1002 

Rock  Island.  . 

Illinois... 

0.006 

98.55 

058 

042 

These  rocks  all  belong  to  the  same  geological  formation,  but  it  is 
seen  that  the  amount  of  dolomite  corresponding  to  one  of  calcite  in 
these  rocks  increases  northward  from  Rock  Island,  both  through 
various  formations,  as  along  the  Mississippi  river  and  also  in  the 
same  geological  formation,  as  in  the  direction  of  the  Cedar  river; 
only  the  rate  of  increase  in  this  latter  section  is  not  as  great  as  in 
the  former. 

The  origin  of  these  peculiar  dolomitic  rocks  is  still  a  mystery, 
notwithstanding  all  that  has  been  written  on  that  subject,  and  we 
can  hardly  wonder  that  it  is  so  when  we  see  that  the  real  constitu- 
tion of  these  rocks  never  before  has  been  properly  expressed.  It  is 
only  when  a  great  fact  is  clearly  recognized  by  itself,  that  we  can 
hope  at  all  to  account  for  it. 

SECTION  FROM  JOHNSON  COUNTY  TO  FREMONT  COUNTY. 
RESULTS   CALCULATED    FROM   MY   OWN   ANALYSES. 


1 

1 

^ 

LOCALITY. 

COUNTY. 

DISTANCE. 

_o 
1 

Calcite. 

Dolomite. 

Insoluble. 

Others. 

10 
246 

132 

Clark's  Mill,  Iowa  City.  . 
Section  20,  township  72, 
range  28  

Johnson  .  . 
Union.  .  .  . 
Fremont.  . 

140  miles. 
90  miles 

0.00 
0.00 
0.006 

96.50 
81,45 
94.81 

trace 
6.63 

3.50 
13.28 
3.65 

5.27 
1.34 

Three  miles  above  Plum 
Hollow  

So  that  the  calcareous  rocks  in  Southern  Iowa  are  almost  pure 
limestones  (calcite). 

Besides  these  sections,  based  upon  quantitative  determinations, 
qualitative  analyses  have  been  made  sufficient  to  determine  the  nature 
of  the  calcareous  rocks  in  two  more  sections  in  southern  Iowa.  The 
presence  of  dolomite  in  a  rock  is  usually  characterized  by  a  peculiar 


REPORT  OF  STATE  GEOLOGIST. 


245 


aspect,  due  to  small,  crystaline,  reflecting  spangles  in  the  rock.  The 
State  Geologist,  judging  from  the  appearance  of  the  rocks  in  south- 
western Iowa,  concluded  the  absence  of  dolomite  in  the  same ;  the 
following  analyses  will  show  that  he  was  right,  or  that  the  calcareous 
rocks  of  this  region  of  this  State,  mostly  belonging  to  the  upper 
coal  -  measures,  are  indeed  very  nearly  devoid  of  dolomite. 


CHEMICAL  SECTION  — FIRST  TIER  OF  COUNTIES. 


11 

LOCALITY. 

DIS- 
TANCE. 

COUNTY. 

PER  CENT 
DOLOMITE. 

249 

LoDsr  Creek  township 

70  miles 

Decatur. 

Faint  trace 

137 

70  miles 

Page  (north  part). 

Faint  trace 

135 

Wilson's  quarry,  3  miles   above 
Plum  Hollow 

Fremont. 

Faint  trace 

132 

Wilson's  quarry,  3  miles  above 
Plum  Hollow.   . 

Fremont.  .  . 

0.63 

CHEMICAL  SECTION -THIRD  TIER  OF  COUNTIES. 


10 
252 

108 
83 
84 
77 
85 
91 
118 

Coral  Mills,  near  Iowa  City  
Coral  Mills,  near  Iowa  Citv  

75  miles. 
75  miles. 
57  miles. 
12  miles. 
12  miles. 
44  miles. 
44  miles. 
34  miles. 

Johnson  

None.  . 

None.  . 

Pel  la 

Marion               .    .  . 

None  
Trace  
Trace  .  . 

No  9  of  Winterset  Section  .  . 

Madison     .        ... 

No.  IS  of  Winterset  Section  
Above  building  laver  

Madison(west  line.) 
Madison  (west  line.) 

Trace  

T3uildin°*  layer 

Trace 

Lewis              .       .  .      . 

Faint  trace. 
Faint  trace. 

Merrett's  quarry,  6  miles  north  of 
Council  Bluffs  

Pottawattamie  

The  preceding  embraces  all  the  systematic  knowledge  of  Iowa 
Rocks  hitherto  brought  to  light.  I  hardly  need  to  say  that  it  is 
very  little  positive  knowledge  for  .so  vast  a  field !  The  chemical 
sections  run  are  few  in  number,  and  the  point  really  determined  in 
these  few  lines,  are  very  far  apart.  In  this  field  very  much  remains 
to  be  done. 

An  artesian  well  1,125  feet  deep,  has  been  bored  at  Mount 
Pleasant,  Henry  county,  for  the  Iowa  Hospital  for  the  Insane.  A 
very  complete  set  of  the  borings  has  liberally  been  presented  to  the 
State  University.  Of  these  I  have  analyzed  the  following  nine 
portions,  corresponding  to  the  depth  indicated,  thus  giving  us  some 
fixed  points  in  an  admirable  verticle  section  of  the  Iowa  rocks,  of 
more  than  a  thousand  feet. 


216 


REPORT  OF  STATE  GEOLOGIST. 
VERTICAL  SECTION  AT  MT.  PLEASANT. 


a^ 
^ 
p.  a 

CHARACTER  OF   CALCAREOUS 
ROCK 

Ratio. 

Calcite. 

Dolom- 
ite. 

Insolu- 
ble. 

Others. 

160 
200 
300 
400 
500 
600 
718 
990 
1095 

Dolomilic  limestone  

0.5 
0.03 
1  .8 

30.07 
75.70 
6.37 

15.22 
2.20 
11.21 

4874 
2033 
79.96 
75.16 
82.88 
59.14 
66.79 
27.19 
626 

5.35 
1.76 
5.22 
4.78 
7.93 
1.37 

Calcareous  dolomite 

Calcareous  dolomite.    .  . 

2.1 
2.2 
26.0 
28.1 

2.93 
1234 
1.16 

229 

6.25 

27.29 
3017 
6440 
8269 

Calcareous  dolomile 

Nearly  pure  dolomite  .     ... 

Nearly  pure  dolomite  

5.98 
0.06 

Maarnesian  dolomite,  infinite. 

One  thousand  one  hundred  and  five  feet  were,  by  the  Geologist, 
supposed  to  correspond  with  the  Hudson  shales  which  outcrop 
near  Dubuque.  From  Mount  Pleasant  to  the  direction  of  the  out- 
crop of  these  shales  in  northeastern  Iowa  is  nearly  one  hundred 
and  ten  miles.  The  vertical  thickness  of  rock  of  one  thousand  one 
hundred  feet  at  Mount  Pleasant  thus  corresponds  to  one  hundred 
and  ten  miles  in  a  horizontal  direction  at  right  angles  to  the  line  of 
outcrop  ;  or  one  mile  in  a  horizontal  direction  northeast  from  Mount 
Pleasant  corresponds  to  ten  feet  in  the  vertical  direction  at  Mount 
Pleasant.  On  Hall's  geological  map  of  Iowa,  the  outcrop  of  the 
dolomite  (Le  Claire' limestone)  is  very  nearly  sixty  miles  distant  from 
Mount  Pleasant;'  accordingly  it  might  here  be  met  at  a  depth  of  six 
hundred  feet.  The  above  chemical  section  of  the  boring  shows  the 
dolomite  to  be  at  seven  hundred  and  eighteen  feet ;  so  chat  we  may 
suppose  the  rocks  to  be  very  uniform  in  their  extent  below  the  sur- 
face. A  very  noteworthy  circumstance  forms  the  regular  increase 
of  the  ratio ;  the  relative  amount  of  dolomite  is  slowly  increasing 
from  three  hundred  to  six  hundred  feet,  corresponding  to  a  slow 
increase  in  the  surface  rocks  for  a  distance  of  thirty  miles.  Now 
this  is  not  observable  in  the  Misissippi  section  ;  but  in  the  Cedar 
river  section  a  similar  increase  was  noticed.  Again,  in  the  short 
distance  of  twelve  miles,  between  Rock  Island  and  Le  Claire,  the 
rock  almost  suddenly  changes  from  pure  limestone  (calcite)  to  dolo- 
mite ;  then  twelve  miles  would  correspond  at  Mount  Pleasant  to  one 
hundred  and  twenty  feet  in  depth ;  and  it  must  be  a  very  striking 
coincidence  that  my  analyses  find  at  a  depth  of  six  hundred  feet 
only  a  ratio  of  two,  and  about  one  hundred  and  twenty  feet  deeper 


EEPORT  OF  STATE  GEOLOGIST.  247 

a  sudden  increase  of  this  ratio  to  twenty  •  six.  It  may  therefore  be 
considered  as  tolerably  well  proved  by  this  chemical  section  that  the 
rock  corresponding  to  Hall's  so-called  Le  Claire  limestone  commences 
at  Mount  Pleasant  at  a  depth  of  very  near  seven  hundred  feet. 

This  fact  is  of  great  importance  in  regard  to  the  dip  of  the  coal- 
bearing  rocks  of  the  State  ;  and  for  this  reason  I  intend  to  analyze 
still  more  of  the  borings  of  the  artesian  well  at  Mount  Pleasant. 

In  conclusion,  I  would  add,  that  the  excess  of  magnesia  in  my 
analysis  of  the  sample  from  the  depth  of  one  thousand  ninety -five 
feet,  corresponds  to  the  excess  of  magnesia  in  Whitney's  analysis  of 
the  Dubuque  dolomite. 


ON  THE  COMPOSITION,  VALUATION  AND  PROXIMATE  ANALYSIS 

OF  IOWA  COALS, 


CHAPTER    III. 

The  following  two  papers  have  appeared  in  the  American  Journal 
of  Mining,  of  New  York,  for  November  30,  December  28,  1867  and 

January  4,  1868. 

\ 

I.      ON  THE   COMPOSITION  AND   VALUATION   OP  IOWA  COALS. 

Before  entering  upon  the  analyses  of  the  numerous  samples  of 
coal  submitted  to  me  by  the  State  Geologist,  Dr.  C.  A.  White,  I 
carefully  reviewed  the  analyses  of  Prof.  Whitney,  recorded  in  Vol.  I. 
of  the  Geology  of  Iowa. 

Prof.  Whitney  has  determined  the  proximate  constituents  of  six- 
teen samples  of  Iowa  coal,  and  reduced  the  same  to  212°  F ;  that  is, 
while  excluding  the  moisture,  he  retains  the  ashes  of  the  coal  in  his 
final  statement. 

Thinking  that  the  combustible  part  of  the  coal  alone  can  be  con- 
sidered as  the  mineral,  so  that  the  ashes  as  well  as  the  moisture 
ought  to  be  excluded  as  accidental  and  really  injurious  constituents 
of  the  coal,  I  reduced  the  analyses  of  Whitney  to  the  combustible 
=  100 ;  the  result  of  this  reduction  is  given  in  a  diagram,  the  scale  of 
which  is  1  millimeter  to  each  per  cent  (or  100  =  100mra  =  1  decimeter.) 
The  fixed  part  of  the  combustible  we  will  call  carbon,  the  volatile  we 
term  bitumen.  The  figures  at  the  lower  line  indicate  the  order  in 
which  these  analyses  are  recorded  in  the  Geology  of  Iowa,  Vol.  I., 
Part  1,  pp.  397-415,  (1858). 


REPORT  OF  STATE  GEOLOGIST. 


249 


I  regret  that  the  diagram  here  referred  to  can  not  be  printed  in 
this  publication ;  I  must,  therefore,  be  satisfied  by  inserting  the 
table  from  which  the  diagram  was  constructed. 


TABLE  OF  REDUCED  RESULTS. 

COMBUSTIBLE  OF  =  100.    ASH  EXTRA.      ANALYSES  OP  PROF.  WHITNEY. 


g' 

LOCALITY. 

BITUMEN. 

ASH. 

I 

8 

4 

I 

7 

9 
10 
11 
12 
153 
14 
15 
1C 

New  Buffalo  

47.14 
44.13 
41.54 
4196 
42.59 
47.17 
41.14 
44.53 
4216 
45.55 
45.18 
4658 
44.92 
45.94 
45.01 
48.38 

25.76 
10.27 
124 
7.11 
13.91 
405 
2.56 
6.87 
7.94 
4.42 
8.47 
7.92 
9.22 
23.44 
1030 
6.30 

New  Buffalo  

Rock  Island  

La  Salle,  lower  seam  

Hillsborough,  Cox'  bank  

Hillsboroueh,  Grail's  bank  

Farmington,  two  miles  above  

Farmington    half  mile  from  

Fort  Dodge,  west  bank  of  river  

Section  18  township  88,  range  28  

Section  13  township  88,  range  28  

Eldora,  Hardin  county  

Newton,  Jasper  county  

Mean  of  all  

44.00 

A  mere  glance  at  this  table  shows  that  the  great  difference  between 
these  Iowa  coals  is  due  to  this  varying  per  centage  of  ashes,  while 
the  per  centage  of  the  carbon  and  bitumen  in  the  combustible  remain 
essentially  the  same  in  all  the  coals,  deviating  but  little  from  the 
mean  of 


which  mean  is  represented  by  the  straight  line  A  B  in  the  diagram. 
If,  instead  of  comparing  all  the  coals  of  Iowa,  we  limit  ourselves 
to  the  coals  of  any  one  county,  the  uniformity  of  the  combustible 
becomes  still  more  apparent. 

WEBSTER  COUNTY. 


No. 

• 

WHITNEY. 

HINRICHS. 

Bitumen.)  Ash. 

Bitumen 

Ash. 

12 
13 
14 



43.16 
41.13 
37.21 

40.50 

7.34 

8.44 
18.19 

4658 
44.92 
45.94 

45.82 

792 
9.22 
23.94 

:  :  ::.v.v:.v.v  .v.v.'.v.'.'  i  v  Y.V.'.Y.'.Y.'.".  . 

Mean  

32 


250 


REPORT  OF  STATE  GEOLOGIST. 


The  deviations  from  the  mean  values  are,  according  to 

No.  12.       No.  13.  No.  14. 

Whitney +2.66      +0.63  -3.29 

Hinrichs +0.76      —0.90  +1.12 

Or,  according  to  my  reduction,  the  several  samples  differ  hardly 
more  than  the  possible  errors  of  the  analyses.  The  proper  com- 
parison of  these  deviations  we  obtain  by  taking  the  sum  of  their 
squares ;  these  are  for  Whitney's  figures,  18.2966,  for  mine  only 
1.4020,  or  fully  thirteen  times  less  !  According  to  Whitney's  state- 
ment these  three  samples  of  coal  from  three  different  localities  in 
Webster  county  appear  to  differ  by  fully  six  per  cent  in  the  amount 
of  bitumen  ;  according  to  my  reduction  there  is  only  an  extreme 
variation  of  one  and  one  -  half  per  cent. 

It  is  therefore  manifest  tbat  by  throwing  out  not  only  the  moisture 
(as  Whitney  has  done),  but  also  the  ashes,  as  accidental,  then  these 
coals,  analyzed  by  Whitney,  differ  not  more  in  regard  to  the  com- 
position of  the  combustible  than  the  errors  of  the  different  analytical 
determinations  of  the  same  sample  of  coal : 

Of  Illinois  coal,  analyzed  by  Whitney,  we  have  the  following : 


No. 

Locality. 

WHITNEY. 

HINRICHS. 

Bitumen. 

Ash. 

Bitumen. 

Ash. 

3 
4 
5 

Kock  Isliinil                                         

41.03 
39.17 
37.39 

39.20 

1.12 
664 
12.21  j 

41.54 
41.96 
42.59 

42.03 

1.24 
7.11 
13.91 

which  show  the  following  deviations  from  the  mean : 

No.  3.         No.  4.  No.  5. 

Whitney +1.83     —0.03  -1.84 

Hinrichs —0.49     —0.07  +0.56 

Dr.  Blaney,  Chemist  of  the  Illinois  survey,  has  analyzed  thirteen 
samples  of  coal  from  Mercer  county,  Illinois,  which  fully  confirm  the 
uniformity  of  the  combustible  for  that  county,  although  the  result, 
as  stated  by  him,  show  an  apparent  variation  of  14  per  cent  (from 
19.2  to  33.3)  in  the  amount  of  bitumen!)  [See  Illinois  Report, 
1866,  Vol.  I,  p.  276.] 


REPORT  OF  STATE  GEOLOGIST. 


251 


MERCER  COUNTY,  ILLINOIS. 


"NTr» 

BLANEY. 

HINRICHS. 

JNO. 

Bitumen. 

Deviation. 

Bitumen.         |       Deviation. 

3 

29.8 

—0.05 

36.52 

4-0.12 

4 

28.6 

—1.25 

36.86 

+0.46 

5 

33.4 

4-3.55 

38.38 

4-2.98 

6 

31.2 

-f-1.35 

35.61 

—0.89 

7 

30.8 

4-0.95 

35.16 

—1.24 

8 

19.2 

—10.65 

35.04 

—1.36 

9 

30.8 

4-0.95 

36.67 

4-0.27 

10 

30.0 

4-0.15 

35.21 

—1.19 

11 

31.2 

4-1.35 

37.32 

+0.92 

12 

32.2 

4-2.35 

36.43 

+0.03 

13 

31.2 

4-1.35 

36.28 

—0.12 

Mean... 

29.85 

36.4 

Sum  of  squares  

140.41 

15  64 

Probable  error... 

2.50 

0.83 

The  sum  is,  by  my  calculation,  reduced  to  one  -  ninth,  the  probable 
error  to  one  -  third,  of  what  they  are  for  Blaney's  values ;  and  the 
example  No.  8,  deviating  fully  10  from  Blaney's  mean,  shows  only  a 
deviation  of  1J  according  to  my  reduction. 

These  examples  are  deemed  sufficient  to  prove  that  even  over  a 
considerable  area  we  may  consider  the  relative  proportion  of  carbon 
and  bitumen  in  our  Western  coals  as  constant. 

Thereby  these  proximate  analysis  of  coals  acquire  a  new  and  more 
important  value  ;  for  if  the  combustible  part  in  the  coals,  compared 
with  one  another,  is  of  the  same  composition,  its  heating  effect  will 
necessarily  be  the  same  for  equal  weights  of  combustible ;  or,  in 
other  words,  the  value  of  these  coals  will  be  proportional  to  the  per 
centage  of  this  combustible  in  the  raw  coal. 

Furthermore,  the  heating  effect  of  two  weights  of  different  coals 
will  be  the  same  if  both  contain  the  same  amount  of  this  combusti- 
ble (say  100) ;  the  amount  of  moisture  and  ashes,  calculated  for  100 
combustible  and  added  to  this  will  therefore  be  the  caloric  equivalent 
of  these  coals,  or  represent  such  weights  of  the  raw  coal  as  will 
produce  the  same  heating  effect,  namely  that  of  100  pure  combus- 
tible. 

Thus  the  coals,  numbers  twelve  and  fourteen,  from  Webster 
County,  Iowa,  contain  respectively  80.6  and  73.4  of  combustible; 
hence  these  figures  express  the  value  in  cents  of  a  weight  of  the 


252 


REPORT  OF  STATE  GEOLOGIST. 


coal  equal  to  one  dollar's  worth  of  pure  combustible ;  furthermore, 
the  amount  of  moisture  and  ashes  is  per  100  combustible  respec- 
tively 24.1  and  36.3:  hence  the  caloric  equivalents  of  these  coals 
would  be  124.1  and  136.3,  that  is,  it  would  require  124.1  pounds  of 
the  former  and  136.3  pounds  of  the  latter,  to  produce  as  much  heat 
as  100  pounds  of  the  pure  combustible,  free  from  ash  and  moisture. 

This  valuation  of  coals  we  believe  as  accurate  as  any  other  theo- 
retical one  in  use ;  and  it  has  this  advantage,  that  it  needs  no  extra 
work  beyond  that  of  the  proximate  analysis,  which  for  many 
reasons,  ought  never  to  be  omitted. 

To  directly  compare  our  valuation  with  that  based  upon  the 
reduction  of  lead,  I  may  refer  to  the  seven  hundred  analyses  of 
Austrian  coals  recorded  in  Jahrbuch  der  K.  K.  geologischen  Reich, 
sanstalt,  Bd.  X.,  Heft  3,  Wien,  1859.  Here  we  find  six  analyses  of 
coals  from  Mihalkovitz,  in  Moravia,  by  W.  Mrazek,  viz. : 


Ashes. 

Water 

Combustible. 

Lead 
1  Coal.l 

reduced  by 
1  Combustible. 

1  Bank  upper 

174 

101 

81  59 

2399 

2940 

1  Bank  lower  

49 

1  06 

9404 

2835 

30  17 

2  Bank 

55 

1  18 

9332 

2718 

29  13 

3  Bank      

5  1 

089 

9401 

2845 

3027 

4  Bank  

29 

1  02 

9608 

2758 

2870 

5  Bank 

68 

008 

93  12 

27  21 

29  16 

Mean  

27  13 

29  47 

The   deviations  from  the  mean  are,  according  to -the  reductions  of 
Mrazek,    —3.14   +1.22   +0.05  +1,32  +0.45   +0.08 
Hinrichs,  —  0.07  +0.70  —0.34  +0.80  —0.77  —0.31 

Of  which  the  latter  are  all  very  much  smaller  than  the  former, 
and  hardly  surpass  the  deviations  between  different  determinations 
of  the  same  sample.  Practically,  one  hundred  of  the  combustible 
matter  in  any  of  the  above  coals  reduced  the  same  amount  of  lead 
(29.5  parts). 

If  we,  therefore,  calculate  the  caloric  equivalent  from  the  per 
centage  of  combustible  matter  in  these  coals,  .as  shown  above,  and 
divide  this  by  the  equivalent  determined  by  the  lead -reduction,  we 
ought  to  get  the  same  quotient  always.  I  find  this  quotient  to  be 
respectively 

12.63          12.96    e     12.75         12.97         12.53        12.63 
of  which  the  mean  is  12.74. 


REPORT  OF  STATE  GEOLOGIST. 


253 


Dividing  my  equivalents  of  these  coals,  or  respectively 

122.6        106.3          107.2         106.4         105.5        107.4 
by  this  quotient  12.74  we  ought  to   obtain   the  same  equivalent  as 
directly  determined  by  Mrazek ;  we  find  the  equivalents  : 


OBSERVED. 

CALCULATED. 

DIFFERENCE. 

1  Bank,  upper  

9.7 

9.72 

—0.08 

1  Bank,  lower  

8.2 

8.34 

+  0.14 

2  Bank     

8.4 

8.41 

+  0.01 

3  Bank   

8.2 

8.35 

+  015 

4  Bank     

8.4 

8.25 

—013 

5  Bank  . 

8.5 

8.43 

—0.07 

It  thus  appears  that  the  extra  reduction  determination  of  Mrazek 
was  superfluous,  for  the  comparison  of  the  value  of  these  coals; 
for  my  equivalent  calculated  from  his  proximate  analysis  fully  agrees 
with  the  equivalent  directly  determined  by  him. 

The  preceding  is  determined  sufficient  to  warrant  the  following 
deductions  : 

1.  The  ashes  as  well  as  the  moisture  of  coals  are  to  be  con- 
sidered as  impurities,  the  combustible  part  being  the  real  mineral 
species. 

2.  This  combustible  part  of  our  Western  coals  is  very  uniform  in 
composition,  even  for  considerable  parts  of  the  coal  -  field. 

3.  For  such  portions  of  the  coal  field  the  value  of  the  coal  is 
measured  by  the  per  centage  of  combustible,  and 

4.  The  caloric  equivalent,  that  is,  the  number  of  pounds  of  coal 
having  the  same  heating  effect  as    100   of  the  pure  combustible,  is 
obtained  by  the  proportion 

,  Equivalent    :    100  =  100    :    value. 
Or  by  dividing  the  value  into  10,000. 

Having  completed  an  extensive  series  of  analyses  of  coals  from 
Iowa,  conducted  according  to  a  uniform  method,  the  result  of  a 
special  series  of  experiments,  I  am  in  the  position  to  add  to  this 
notice,  that  not  only  the  general  uniformity  over  considerable  areas 
is  confirmed,  but  the  change  in  this  composition  in  the  various  parts 
of  the  coal  -  field  seems  to  lead  to  still  more  general  results'. 

Thus  by  comparing  the  Iowa  coals  with  those  of  Illinois,  analyzed 


254  REPORT  OF  STATE  GEOLOGIST. 

by  Prof.  Blaney,  I  find,  after  reducing  these  latter  analyses,  that  in 
the  Illinois  coal-field  the  per  centage  of  bitumen  appears  to  increase 
westward.  For  I  find,  as  means,  for 


NO.    OF 
ANALYSES. 

LOCALITY. 

PER  CENT 
BITUMEN. 

4 

Grundy  county,  Illinois  *.  

32 

8 

La  Salle  county,  Illinois  

33 

2 

35 

16 

Warren  and  Mercer  counties,  Illino  s  

36 

These  analyses,  all  executed  by  Prof.  Blaney,  may  be  considered 
comparable.  So  also  the  following  analyses  of  Prof.  Whitney,  given 
above. 

No.  3,  4,  5 Illinois Mean  42  per  cent   bitumen. 

The  other  13  Iowa Mean  44  per  cent   bitumen. 

From  my  own  analyses,  recorded  in  Chapter  I,  Section  4,  it 
appears  that  westward  in  the  Iowa  coal  -field,  the  amount  of  bitumen 
again  decreases  (about  4  per  cent.) 

As  far  as  the  facts  in  regard  -to  this  very  important  question  are 
known,  it  seems  that  the  greatest  amount  of  bitumen  is  found  in  that 
part  of  Jie  coal  -field  near  the  course  of  the  Mississippi,  and  that  also 
on  the  whole  the  amount  of  bitumen  is  greater  for  Iowa  coals  than  for 
Illinois  coals.  (See  American  Journal  of  Mining,  Feb.  1,  1868.) 

II.    ON   THE   PROXIMATE   ANALYSIS   OF    COALS. 

Coal  is  not  a  simple  chemical  combination,  expressible  by  a  chem- 
ical formula ;  but  it  is  the  final  residuum  of  vegetable  matter  having 
been  exposed  to  a  long  -  continued  and  complex  process  of  addition 
and  subtraction.  An  elementary  analysis  will  therefore  not  teach 
us  much  in  regard  to  the  nature  of  the  combustible ;  for  who  would 
dare  to  make  any  conclusion  concerning  the  peculiar  combination  of 
the  elements  thus  determined  ?  Even  the  heating  effect  calculated 
from  this  elementary  analysis  is  not  more  trustworthy  than  the  val- 
uation by  the  reduction  of  lead. 

The  proximate  analysis,  on  the  contrary,  enables  us  to  learn  some- 
thing in  regard  to  the  real  nature  of  the  fuel.  The  moisture  and 
the  ashes  are  both  not  only  diluents  of  the  fuel,  but  in  themselves 
obstacles  to  the  effectiveness  of  the  same ;  the  vaporization  of  the 
moisture  causes  a  serious  loss  of  heat,  while  the  ashes,  by  hindering 


REPORT  OF  STATE  GEOLOGIST.  255 

a  complete  combustion,  and  by  the  heat  they  contain  when  dropped 
through  the  grate,  constitute  another  loss.  By  furthermore  deter- 
mining the  total  amount  of  volatile  matter,  we  learn  both  the  per 
centage  of  coke  in  the  fuel,  and  the  amount  of  carbon  (fixed  com- 
bustible) and  bitumen  (volatile  combustible  matter).  Although 
neither  of  these  two  products  can  be  considered  as  simple  chemical 
compounds,  it  is  nevertheless  of  the  utmost  practical  importance  to 
know  these  two  quantities,  because  of  the  great  importance  of  coke 
and  gas  in  the  arts.  The  yield  in  gas  of  a  fuel  is  no  doubt  measured 
by  the  per  centage  of  bitumen,  at  least  for  coals  from  the  same 
basin  —  coals  which  therefore  may  be  supposed  to  have  passed 
through  nearly  the  same  chemical  history. 

In  taking  charge  of  the  chemical  labors  of  the  Geological  Survey 
of  Iowa,  I  had  grave  doubts  H  regard  to  the  value  of  this  proximate 
analysis  of  coals.  No  investigation  as  to  its  accuracy,  nor  as  to  the 
best  method  of  conducting  the  work,  had  come  to  my  knowledge. 
The  European  chemists  seem  almost  exclusively  to  rely  on  the 
elementary  analysis,  while  in  the  great  Government  surveys  ot  this 
country  the  proximate  analysis  seems  to  have  been  almost  as  exclu- 
sively practised.  But  while  the  former  may  readily  be  turned  into 
approximate  determinations  of  the  heating  effects  of  the  fuel,  the 
latter  have,  to  my  knowledge,  never  been  used  for  such  purposes,  nor 
was  it  at  all  apparent  that  they  ever  could  be  thus  made  useful. 

In  regard  to  the  first  condition  of  all  quantitative  determinations, 
that  of  giving  constant  results  for  the  same  substance,  but  few 
observations  were  accessible,  and  these  rather  increased  my  first 
distrust.  Thus  Whitney  nowhere,  in  his  report  on  the  coals  of  Iowa, 
(Geology  of  Iowa,  Vol.  I,  Pt.  I),  gives  any  data  whatever  in  regard 
to  this  most  important  question,  although  he  devotes  a  very  large 
space  to  the  subject.  Only  the  final  results  are  given  ;  but  whether 
the  individual  determinations  deviated  much  or  little  from  the  same, 
can  not  be  ascertained ;  or,  in  other  words,  the  degree  of  accuracy  or 
reliability  of  his  reported  results  is  altogether  unknown.  The  report 
of  Dr.  James  Y.  F.  Blaney  on  the  coals  of  Illinois  (Geology  of  Illinois, 
Vol.  I,  1866,  p.  258-277)  insists  on  the  great  correspondence  of  the 
amount  of  bitumen  volatalized  to  varying  circumstances,  but  only  in 


256  REPORT  OF  STATE  GEOLOGIST. 

general  terms  :  no  experimental  data  being  brought  forward.  Fortu- 
nately, this  chemist  gives  for  four  samples  of  coal  the  direct  result  of 
two  determinations  (see  p.  275) ;  but  the  differences  between  these 
two  determinations  on  the  same  sample  are  respectively  : 

3.04  1.50  1.32  0.07 

per  cent,  the  mean  of  which  is  1.48,  or  very  nearly  one  and  a  half 
per  cent.  This  result  certainly  was  not  calculated  to  incline  me 
favorably  to  the  proximate  analysis  of  coals. 

On  the  other  hand,  the  usual  applications  of  coal  demand  such 
analysis,  and  my  reduction  of  the  analysis  of  Whitney  and  Blaney 
proves,  by  the  results  obtained,  that  the  determinations  must  be  more 
reliable  than  the  above  figures  would  indicate. 

It  thus  became  necessary  for  me,  before  making  any  proximate 
analysis  of  the  many  samples  of  Iowa  coals  put  into  my  hands  by  the 
State  Geologist,  Dr.  C.  A.  White,  to  make  a  rather  extensive  and 
thorough  search  into  the  method  itself,  in  order  to  study  its  exact 
value.  Since  I,  in  these  determinations  according  to  the  varied 
circumstances  for  the  same  sample  of  coal,  obtained  values  ranging 
from  41.77  to  57.31  per  cent  for  the  amount  of  volatile  matter,  it 
seems  not  only  that  such  investigation  was  sufficiently  called  for,  but 
even  that  it  shows  the  proximate  analysis  to  be  worthless  :  a  variation 
of  15.54,  or  rather  16  per  cent  for  the  same  sample,  seems  to  condemn 
the  method  admitting  of  such  results. 

In  the  determination  of  magnesia,  as  large  variations  could  be 
obtained  by  exposing  the  crystalized  double  phosphate  to  varied 
conditions ;  and  yet  this  determination,  properly  executed,  is  one  of 
the  most  accurate  known  in  analysis. 

It  is  easily  seen  that  the  following  elements  will  modify  the  result 
of  the  amount  of  volatile  matter  driven  off  from  a  sample  of  coal 
contained  in  a  covered  platinum  crucible :  weight  of  coal  and  of 
crucible;  degree  and  duration  of  heat;  condition  of  coal.  I  hope  to 
show  that  this  determination,  notwithstanding  all  these  elements, 
admits  of  an  accuracy  of  one  -  tenth  o'f  a  per  cent,  equal  to  that  of 
weighing  a  gramme  exact  to  the  milligramme. 

The  sample  of  coal  used  for  this  purpose  was  not  selected,  but  taken 
at  random.  It  was  labelled  No.  350,  and  is  from  the  bottom  of 


HEPOKT  OF  STATE  GEOLOGIST. 


257 


Roberts  and  Fisher's  Bank,  which  bank  is  five  to  six  feet  thick,  seven 
miles  west  of  the  town  of  Pella,  in  Marion  county,  Iowa.  From  this 
sample  a  very  pure  piece,  free  from  any  visible  admixture  of  either 
gypsum  or  pyrites,  was  selected.  By  means  of  2.760  coal,  in  coarse 
fragments  of  about  1-10  cubic  centimenter  and  a  50  -  gramme  flask, 
the  specific  gravity  of  this  coal  was  found  to  be  1.328. 

A.     DETERMINATION   OF   THE   VOLATILE   MATTER. 

SOURCE  OF  HEAT. — A  common  Bunsen  burner  was  used  (red  heat), 
and  also  a  gas  burner  with  six  jets,  surmounted  by  a  French  soufflet- 
cyliridrique  (white  heat),  care  being  taken  to  keep  the  gas  -  cock  in 
the  same  position  by  means  of  an  arm  of  ten  inches  in  length.    These 
two  sources  of  heat  we  will  denote  respectively  "  B  B,"  and  "  Blast." 

The  time  was  usually  measured  by  means  of  a  small  sand  -  glass, 
running-  exactly  three  and  one  -  half  minutes  ;  this  duration  we  will 
denote  by  t.  Thus  BBtf  means  that  the  crucible  was  exposed  to  the 
constant  flame  of  the  Bunsen  burner  during  three  and  one  -  half 
minutes. 

INFLUENCE   OF   QUANTITY   OF   COAL. 

1.     Coal  pulverized,  not  dried ;  heat:  BB£;  cooled  and  weighed 
then  blast,  i;  then  weighed  again.* 


NO.  OF 

EXPER'T. 

WEIGHT. 

VOLATILE, 
PER  CENT. 

DEVIATION. 

^CRUCIBLE. 

d 

5.360 

48.24 

—1.14 

19.2 

n 

1.910 

49.58 

+0.20 

19.2 

e 

1.147 

49.87 

+0.49 

11.6 

0 

1.031 

49.85 

+0.47 

9.4 

M 

ean.. 

49.38 

2.     Coal  in  small  fragments  ;  heat  as  in  1. 


h 
9 

3.743 
1.130 

48.30 
50.18 

—0.94 
+0.94 

19.2 
9.4 

M 

ean.. 

49.24 

*  Weight  =  coal  taken  in  grammes ;  crucible  =  weight  of  the  same.  Deviation 
per  cent  from  the  mean  given.  These  quantities  are  given  in  the  same  order  in 
all  subsequent  tables,  unless  stated  otherwise. 

33 


258 


KEPORT  OF  STATE  GEOLOGIST. 


For  the  same  heat,  the  amount  volatilized  is  the  greater,  the  smaller 
the  mass  heated;  whether  the  coal  is  in  small  fragments  or  pulver- 
ized hardly  makes  any  difference ;  but  since  the  bitumen  passed  off 
more  regularly  when  the  coal  was  pulverized,  while,  when  in  frag- 
ments, slight  explosions  sometimes  occurred,  the  coal  should  be  pul- 
verized for  the  determination  of  the  bitumen. 

3.  Coal,  pulverized,  between  1  and  2  grammes ;  heat  as  above, 


NO.  OF 

EXPER'T. 

WEIGHT. 

VOLATILE. 
PER  CENT. 

DEVIATION. 

CRUCIBLE. 

n 

G 
0 

1.910 
1.147 
1.031 

49.58 
49.87 
49.85 

—0.19 

+0.10 
+0.08 

19.2 

11.6 
9.4 

Mean. 

49.77 

giving,  as  probable  error  of  a  single  determination,  only  0.108  per 
cent,  or  only  1  milligramme  for  1  gramme  of  coal.  This  is  not 
greater  than  that  of  the  weighing  itself,  in  which  fractions  of  a 
milligramme  were  usually  neglected. 

4.  Coal,  pulverized  (new  portion),  and  between   1 — 2   grammes. 
Heat:  BBtf;  immediately  thereafter  BlasU,  without  cooling. 


NO.   OF 

EXPER'T. 

"WEIGHT. 

VOLATILE. 
PER  CENT. 

DEVIATION. 

CRUCIBLE. 

a' 
n' 

1.160 

1.040 

50.86 
50.58 

+  0.14 
—0.14 

9.4 

11.0 

Hear 

i.. 

50.72 

Another  determination  was  made  (o') ;  but  on  account  of  side- 
draft  while  over  BB  the  crucible  cooled  several  times ;  correspond- 
ingly the  result  deviated  much,  being  only  49.10. 

From  3  and  4  we  conclude,  that  if  the  substance  taken  is  from  1 
to  2  grammes,  the  result  will  be  constant  for  the  same  mode  of 
heating. 


REPORT  OF  STATE  GEOLOGIST. 


259 


INFLUENCE  OF  DRYING  THE  COAL  BEFORE  IGNITION. 

5.  Coal,  fragments ;  heat,  BB^;  not  cooled;  Blast  £. 


XO.  OP 

EXPER'T. 

WEIGHT. 

VOLATILE. 
PER  CENT. 

DEVIATION. 

t 
u 

V 

1.361 
1.060 
1.030 

48.49 
47.26 
47.43 

+0.76 
-0.47 
—0.30 

Mean 

47.73 

with  the  probable  error  of  one  single  determination  0.45. 

Comparing  this  with  4  (same  heating)  it  appears  that  about  3  per 
cent  less  volatilized  by  previous  drying,  and  also  that 'the  accuracy 
of  one  determination  is  four  times  less  than  when  the  coal  is  ignited 
without  previous  drying.  In  the  arts  the  coal  is  not  artificially  dried 
before  coking.  For  all  of  these  reasons  the  amount  of  volatile 
matter  is  best  determined  on  undried  coal. 

6.  In  general,  I  found,  as  means, 

4  dried  coals  gave  47.97  per  cent  volatile, 
10  undried  coals  gave  49.87  per  cent  volatile, 
confirming  the  above. 

INFLUENCE     OF    COOLING     AFTER     THE     IGNITION    OVER     THE    BUNSEN 
BURNER,  AND  BEFORE   THE  IGNITION   OVER   THE   BLAST  -  FLAME. 

7.  Coal,  pulverized,  not  dried;   heat;  BB£;  then  Blast  t,  without 
cooling. 


NO.  OP 

EXPER'T. 

WEIGHT. 

VOIATILE 
PER  CENT. 

DEVIATION. 

X 

y 

1.314 
1.156 

49.01 

49.05 

—0.02 

+  0.02. 

Mean 

49.03 

which  compared  with  the  corresponding  case  3,  giving  the  mean 
49.77  and  maximum  deviation  0.19,  shows  that  by  the  intermediate 
cooling  about  f  per  cent  more  is  volatilized.  This  probably  is  due 
to  the  fact  that  the  crucible  upon  cooling  is  filled  with  atmospheric 
air,  which,  upon  renewed  ignition,  must  burn  a  corresponding  amount 
of  the  coal. 


260 


REPORT  OF  STATE  GEOLOGIST. 


INFLUENCE  OF   KEPEATED   HEATING,   THE   CRUCIBLE   BEING   AFTER   EACH 
IGNITION   COOLED   AND   WEIGHED. 

8,  Coal=Y=  1.628   in   crucible    19.2   was    dried,   then   ignited, 
(BB()    and  lost   41.77  per  cent.     Being  ignited  again   in  the  same 
way,  it  lost   2.76   per  cent,  or,  in   all,  44.53.     Being  successively 
ignited  7    times,  BB,  each   time   for  6  minutes,    the   total   loss  was 
52.39,  or,  on  the  average  for  each  of  these  6  -  minute  BB  ignitions, 
1.12]  two  of  the  determinations  nearest  this  average  were  1.06  per 
cent). 

Hereafter  the  same  was  5  times  for  3J  minutes  exposed  to  the 
blast;  the  volatile  passed  off  amounted  to  57.31,  giving  for  each  of 
these  last  ignitions  the  average  loss  of  0.98  per  cent. 

It  now  had  been  ignited  14  times,  each  time  having  been  cooled 
and  weighed  ;  and  we  have  14  ignitions,  57.31  volatile:  1st  ignition 
41.77  volatile ;  hence  average  for  each  of  the  13  ignitions  1.195 
or  1.2  per  cent. 

This  series  of  experiments  shows  that  it  is  impossible  to  heat  coal 
until  no  further  loss  is  sustained ;  for  it  is  apparent  that  each  heating 
(after  complete  cooling)  produces,  on  the  average,  more  than  the 
additional  volatization  of  1.  On  1  gramme  coal  taken,  1  per  cent 
carbon  burnt  requires  about  30  milligrammes  or  20  cubic  centimeters 
of  oxygen.  We  may  therefore  consider  these  successes  almost  equal 
losses  due  to  a  real  combustion. 

INFLUENCE  OF  PROTRACTED  HEATING. 

9.  Coal,  pulverized,  not  dried;  heat,  always  first  BB  t,  and  then 
immediately,  without  cooling,  transferred  to  blast -lamp. 


NO. 

WEIGHT. 

BLAST. 

VOLATILE. 

DIFFERENCE 

DIFFERENCE 
PER    MINUTE. 

a'-j-n' 

(mean) 

8  min. 

50.72 

0.57 

0.19 

c' 

6    « 

51.29 

1.04 

0.35 

V 

9    « 

52.33 

1.95 

0.65 

V 

12    « 

54.28 

2.93 

0.16 

k' 

30    " 

57.21 

By  comparing  each  with  the  first  mean,  we  obtain  for  each  minute- 
blast  after  the  first  3,  respectively, 

0.24  0.39  0.27  0.20 

showing  less  difference  than  the  above. 


REPORT  OF  STATE  GEOLOGIST.  261 

The  volatilization,  after  the  three  first  minutes  -  blast,  is  therefore 
increasing  1  to  f  per  cent  for  six  minutes,  and  then  very  slowly 
decreasing  to  about  i  per  cent  for  half  an  hour.  At  this  rate  the 
loss  is  12  per  hour. 

It  is  apparent  that  this  loss  is  less  than  when  cooled  in  the  inter- 
vals, but  it  proves  that  a  slight  current  of  air  must  get  at  the  coal  in 
the  covered  crucible. 

At  any  rate  it  is  demonstrated,  that  the  rule  which  is  sometimes 
given,  to  heat  until  no  further  loss  is  sustained,  demands  an  impossi- 
bility. 

INFLUENCE   OF   THE   DEGREE   OF  HEAT. 

10.  Coal,  pulverized,  not  dried;  heat,  BB£;  cooled  and  weighed; 
then  Blast  t ;  cooled  and  weighed  again. 

AFTER  BB.  AFTER  BLAST. 


n         1.910 

48.08 

+0.42 

49.58 

—0.18 

e         1.147 

47.69 

+0.03 

49.87 

+0.11 

o         1.031 

47.23 

—0.43 

49.85 

+0.09 

Mean  

47.66 

49.76 

Probable  error.. 

0.284 

0.108 

showing  that  the  higher  temperature  gives  the  most  accurate  results. 

RESULT. 

From  this  investigation  we  conclude  : 

The  total  volatile  matter  of  coal  is  determined  with  accuracy  (1  mgr. 
on  1  gr.  coal)  by  taking  1  to  2  grammes  of  undried  pulverized  coal, 
heating  it  for  3J  minutes  over  a  Bunsen  burner  (bright  red  heat)  and 
then  immediately,  without  cooling,  for  the  same  length  of  time  over  a 
blast  gas  -  lamp  (white  heat.) 

B.   DETERMINATION   OF   THE  MOISTURE. 

A  flat  -  bo.ttomed  iron  pan,  of  20  centimeters  in  diameter,  was  filled 
evenly  to  the  depth  of  1J  centimeters,  with  sand,  and  the  latter  was 
covered  with  a  copper  plate,  on  which  the  watch  -  glass  containing 
the  coal  was  placed.  A  thermometer  (scale  to  370°C.)  was,  by  means 
of  a  rubber  stopper,  inserted  in  an  iron  arm  of  the  tripod  supporting 
the  iron  pan,  and  held  with  its  bulb  about  half  a  centimeter  above 


262 


REPORT  OP  STATE  GEOLOGIST. 


the  copper  plate.  By  means  of  a  Bunsen  burner  it  was  found  very 
easy  to  keep  the  thermometer  perfectly  constant  at  115°C.  This 
apparatus  I  consider  a  good  substitute  for  Fresenius'  iron  plate. 

The  coal  to  be  dried  was  finely  pulverized,  direct  experiments 
having  convinced  me  that  the  application  of  fragments  was  not  only 
very  much  slower,  bat  also  erroneous,  on  account  of  the  peculiar 
property  of  bituminous  coal  treated  of  below. 

In  order  to  show  the  accuracy  of  this  method,  I  transcribe  the  fol- 
lowing examples  from  my  journals  : 


No.  of 
coal. 

Weight  of 
portion. 

Time. 

MOISTURE. 

Mean. 

Per  cent. 

Deviation  from 
Mean. 

390  e 

0.961 

1     hour. 

4.888 

—0.004 

4,892 

390  f 

0.919 

1    hour. 

4.896 

+0.004 

4,892 

390  e 

0.961 

2J  hours. 

4.16 

+0.01 

4.15 

390  f 

0.919 

2J  hours. 

4.14 

—0.01 

4.15 

339  e 

1.452 

1    hour. 

8.26 

+0.07 

8.19 

339  f 

0.975 

1    hour. 

8.12 

—0.07 

8.19 

339  e 

1.452 

3    hours. 

7.16 

+0.17 

8.19 

339  f 

0.975 

3    hours. 

6.83 

—0.16 

8.19 

338  e 

1.415 

1    hour. 

3.852 

—0.029 

3.881 

338  f 

0.805 

1    hour. 

3.911 

+0.030 

3,881 

338  e 

1.415 

2|  hours. 

3.287 

+0.123 

3,164 

338  f 

0.805 

2|-  hours. 

3.042 

—0.122 

3,164 

338  e 

1.415 

5J  hours. 

2.722 

+0.088 

2,634 

338  f 

0.805 

5J  hours. 

2.546 

—  0.08S 

2,634 

These  results  —  a  few  taken  from  among  a  great  number  of  deter- 
minations—  show  that  the  loss  (called  moisture)  decreases  regularly 
after  the  first  hour  of  drying,  that  is  to  say,  while  the  coal  loses  in 
weight  during  the  first  hour,  it  steadily  gains  in  weight  thereafter. 
It  appears  furthermore,  that  the  accuracy  of  a  determination,  ex- 
pressed in  the  smallness  of  the  deviations  from  the  mean,  is  greatest 
at  the  end  of  the  first  hour  of  drying,  least  after  about  three  hours 
of  drying,  and  thereafter  increases  again  as  expressed  in  the  dimi- 
nution of  the  deviations  after  five  and  one  -  half  hours  drying  in  coal 
No.  338. 

On  account  of  these  peculiar  properties  of  our  bituminous  coal,  1 
put  down  as  moisture  the  loss  in  weight  of  the  finely  -  pulverized  coal 
after  one  hour's  drying  at  a  temperature  between  105°  and  110°C. 


REPORT  OF  STATE  GEOLOGIST.  263 

C.      ON   THE   SLOW   OXIDATION   OF   COAL. 

This  increase  in  weight  after  the  first  hour's  drying  I  have  found 
in  all  Iowa  coal  investigated  as  yet.  I  have  also  found  it  to  occur  in 
a  sample  of  coal  (steinkohle)  from  Beuthen,  Silesia,  which  showed  a 
loss  of  3.62  per  cent  at  the  close  of  one  hour,  and  in  four  further 
hours'  drying  gained  again  0.42  per  cent ;  also  in  cannel  coal  from 
Wigan,  England,  which  gained  0.42  per  cent.  It  was  not  noticed  in 
brown  coal  from  Bilin,  Bohemia,  nor  in  brown  coal  from  Arbesan, 
Bohemia,  nor  in  bituminous  wood  from  Salzhausen,  Germany,  nor  in 
peat  from  Ireland,  nor  in  anthracite  from  Pennsylvania.  I  am  there- 
fore inclined  to  believe  this  to  be  a  property  peculiar  to  pit  -  coal 
(steinkohle). 

On  page  401  of  Vol.  I.  P.  I.  of  the  Iowa  Geology,  Prof.  Whitney 
remarks  :  "  A  remarkable  fact,  in  connection  with  the  determination 
of  the  water  present  in  the  specimens  of  coal  has  been  noticed.  In 
numerous  instances,  after  the  sample,  in  the  form  of  a  coarse  powder, 
had  been  dried  for  several  hours  in  the  air  bath,  at  a  temperature  a 
little  above  that  of  boiling  water,  during  which  time  it  had  gradually 
lost  weight  until  all  the  water  seemed  to  havcx  been  expelled,  on  con- 
tinuing the  operation  for  some  time  longer  a  slight  increase  of  weight 
would  become  perceptible,  and  the  coal  would  continue  to  grow  heavier 
until  a  gain  of  several  tenths  of  a  per  cent  of  the  original  weight  had 
been  made.  This  appears  to  be  owing  to  the  slow  oxidation  of  the 
sulphur  which  all  these  coals  contain  in  a  finely  divided  state,  dis- 
seminated in  invisible  particles  through  the  mass,  and,  perhaps, 
partly  in  combination  with  iron." 

It  is  evident  that  Prof.  Whitney  failed  to  discover  this  property 
as  a  general  one,  because  he  had  the  coal  in  coarse  fragments.  The 
want  of  correspondence  in  the  results  of  determinations  of  moisture 
in  the  same  sample,  dried  at  the  same  time,  but  of  different  weights, 
made  me  apply  the  coal  in  the  form  of  powder.  Thereby  the  turning 
point  was  reduced  from  "  several  hours  "  to  less  than  one  hour ;  the 
"  numerous  instances"  extended  to  all  samples  investigated;  the 
"  slight  increase  of  several  tenths  of  one  per  cent "  became  often 
two  and  even  four  per  cent !  Instead  of  numerous  exceptions  we 
now  discovered  a  general  law. 


264  REPORT  OF  STATE  GEOLOGIST. 

We  have  failed,  as  yet,  to  notice  any  "  sulphur "  disseminated 
through  the  Iowa  coal ;  what  popularly  is  called  sulphur  is  pyrites. 
Prof.  Whitney  has  given  no  proof  of  the  existence  of  real  "  sulphur" 
in  the  coal.  It  is  therefore  unsatisfactory  to  ascribe  this  property 
of  the  bituminous  coals  to  such  "  sulphur." 

Pyrites  might  well  be  the  cause  of  this  phenomenon  ;  the  red 
ashes  obtained  in  many  cases  (in  Van  Buren  County,  Iowa,  invaria- 
bly from  the  upper  part  of  the  coal  -bank),  may  well  be  ascribed  to 
pyrites  disseminated  through  the  coal  in  invisible  particles.  2 
FeS2  will  give  Fe203,  +4S03,  by  -exactly  doubling  their  weight. 

In  order  to  decide  the  question,  I  select  the  following  results  from 
my  analyses : 

INFLUENCE    OF   TIME    OF   DRYING. 

Top  -  coal.     Number  of  samples,  4  2 

Time  of  drying,  2  3  4-5  hours. 

Mean  gain  per  cent,  0.45        0.71        0.96 

Bottom  coal.     No.  of  samples,  352 

Time  of  drying,  234  hours. 

Gain,  per  cent,  0.49        0.50        0.96 

Mean  of  above.    No.  of  samples,  784 

Time  of  drying,  2  3  4-5  hours. 

Gain,  per  cent,  0.46        0.63        0.96 

Gain,  per  hour,  0.23        0.21        0.24 

or,  on  the  whole,  for  nineteen  samples  of  coal,  very  nearly  propor- 
tional to  the  time,  this  being  not  more  than  four  hours.  It  also 
appears,  that  no  essential  difference  is  apparent  in  regard  to  the 
position  of  the  sample  in  the  coal  -  bank. 


REPORT  OF  STATE  GEOLOGIST. 


265 


By  this  means  we    may   compare    the    following   determinations, 
referring  to  2,  3,  or  4  hours  drying.     We  find :  • 


COAL. 

INCREASE 

PER  CT. 

PLACE 

NO. 

TOTAL. 

PER  HR. 

PIFFERENCE 

COLOR  OF  ASHES. 

i  Top  

390 

2 

0.75 

0.38 

Pale  brown  . 

(  Bottom  . 

884 

2 

0.35 

0.16 

0.22 

White 

I  Bottom  . 
)  Top    . 

395 

375 

4 
4 

0.80 
064 

0.20 
0.16 

1      004 

Red  and  white  
White 

j  Top  .... 
(  Bottom  . 

346 

371 

3 
3 

0.68 
0.45 

0.23 
0.15 

•      0.08 

Reddish  brown  
White  

(  Top  . 

336 

3 

0.76 

0.25 

GPEV              •       •  . 

(  Bottom.  . 

334 

3 

0.58 

0.19 

•      0.06 

Gray  

(  TOP 

333 

3 

1  17 

0.39 

Pink 

(  Bottom  . 

340 

3 

0.91 

0.30 

•      0.09 

(  Middle.. 

357 

3 

0.55 

0.18 

) 

White  

(Top  

370 

3 

0.46 

0.15 

f-      0.03 

Reddish 

Except  in  the  coal  from  the  last  mine,  we  notice  that  the  more 
ferruginous  ash  does  correspond  to  a  slightly  greater  increase  in 
weight ;  but  we  notice  also  that  this  difference  is  but  very  small  as 
compared  to  the  total  amount  of  increase,  being  only  one  -  fifth  to 
one  -  third  of  the  whole.  Arranging  these  coals  in  the  order  of  this 
hourly  increase,  we  find  the  color  of  the  ashes  not  at  all  forming  a 
regular  series  from  white  to  red,  as  it  ought  to  be  if  this  increase 
was  mainly  depending  upon  the  oxidation  of  the  pyrites.  Besides, 
the  mean  of  the  4  white-  ash  coals  is  0.16  per  cent  hourly  increase, 
while  the  mean  of  the  4  coals  showing  the  greatest  increase  is  only 
0.33  per  cent,  or  double  the  former. 

Coal,  333     Increase,  0.39  per  cent. 


34 


390 
340 
336 
346 
395 
334 
357 
375 
384 
371 
370 


o.; 

0.30 
0.25 
0.23 
0.20 
0.19 
0.18 
0.16 
0.16 
0.15 
0.15 


Ash 

a 
a 
a 
« 

:  pink, 
pale  brown, 
light  gray, 
gray, 
reddish  brown. 

a 

red  and  white. 

a 
M 

gray, 
white. 

a 

white. 

tt 

white. 

tt 

white. 

a 

reddish. 

266  REPORT  OF  STATE  GEOLOGIST. 

The  greater  increase  of  the  pyritiferous  coals  is  accounted  for  by 
the  oxidation  of  the  pyrites  they  contain ;  the  comparatively  great 
increase  of  coals  giving  a  pure  white  ash  seems  to  force  the  con- 
clusion upon  us,  that  the  bitumen  of  the  coal  itself  oxidizes,  and  that 
to  this  oxidation  the  main  increase  of  all  these  bituminous  coals  must 
be  ascribed.  Remembering  now  our  result  regarding  the  deportment 
of  bituminous  coal  from  Silesia,  anthracite  from  Pennsylvania,  brown 
coal  from  Bohemia,  (all  of  which  gave  ashes  very  nearly  of  same 
shade,  and  all  of  which  had  been  in  my  air  -  heated  laboratory  for 
two  years),  it  seems  not  unlikely  that  this  is  another  characteristic 
chemical  difference  between  bituminous  coals  and  other  fossil  coals. 

In  conclusion  I  will  only  give  two  additional  determinations,  show- 
ing a  very  considerable  increase  in  weight,  and  also  that  the  process 
of  oxidation  is  completed  in  about  six  hours  for  two  -  thirds  grammes 
of  coal.  For  No.  329,  containing  8.30  per  cent  of  gray  ashes, 
gained,  in  5J  hours,  2.05  per  cent  of  its  original  weight.  Coal  No. 
348,  with  6.00  per  cent  red  ashes,  weighed  0.693. 

Change:  Total  loss: 

Weight.    Per  cent.  Per  cent. 

After  f  hour,  0.630  loss  0.063—9.091  9.091 

"     2  hours,  0.625  "'   0.005—0.722  9.813 

"      5J  hours,  0.656  gain  0.031—4,474  5,339 

"      8f  hours,  0.656  "    0.000  5.330 

D.      DETERMINATION  OF   THE  ASHES. 

The  best  way  to  determine  the  ashes  in  coal  I  found  to  be  the 
coking  of  the  finely  pulverized  coal  in  a  small  platinum  dish  (weigh- 
ing about  8  grammes)  with  subsequent  incineration  of  this  coke  in 
the  same  vessel.  The  incineration  takes  place  with  great  ease  and 
rapidity,  and  the  results  are  perfectly  satisfactory.  Thus  3.022 
grammes  of  coal  No.  333  gave  2.35  per  cent,  and  5.263  grammes  of 
the  same  coal  gave  2.58  per  cent,  deviating  from  the  mean  2.46 
by  +0.11. 

In  regard  to  the  ashes  of  our  Iowa  coals,  I  have  found  that  they 
are  very  much  more  uniform  in  their  distribution  throughout  the 
coal-fields  than  usually  thought  possible.  In  Van  Buren  county,  I 
find  the  "  bottom  "  coal  giving  a  white  or  light  colored  ash,  the  "  top" 
coal  of  the  same  bank  a  red  colored  ash ;  a  fact,  which  I  intend  to 


REPORT  OF  STATE  GEOLOGIST.  267 

make  use  of  in  a  subsequent  paper  on  the  origin  of  our  coal.  I  also 
find  the  amount  of  ashes  to  increase  quite  evenly  (in  this  county), 
toward  the  margin  of  the  coal  -  field,  from  about  2  to  7  per  100 
combustible. 

E.      DETERMINATION   OF   SPECIFIC  GRAVITY. 

Coarse  fragments,  freed  by  means  of  a  sieve,  from  all  small 
particles,  and  averaging  1-10  cubic  centimeters  in  volume,  were 
introduced  into  a  fifty  -  gramme  flask,  provided  with  thermometer 
stopper.  The  constants  for  this  flask,  for  temperatures  varying  from 
50°  to"  80°  F.  had  been  carefully  determined. 

The  given  specific  gravity  corresponds  to  the  coal  perfectly 
soaked,  so  that  all  its  pores  were  filled  with  water.  That  required, 
on  the  average,  twelve  hours,  permitting  two  determinations  per  day, 
one  in  the  morning,  another  in  the  evening. 

That  this  is  not  at  all  trifling,  may  be  seen  from  the  following 
example.  2.760  grammes  coal  (No.  350)  gave  the  specific  gravity 
1.309  at  64°  F.,  immediately  after  filling  the  flask  with  water ;  after 
about  twelve  hours  soaking,  the  specific  gravity  had  increased  to 
1,328,  for  the  same  temperature.  According  to  this  latter  determina- 
tion, a  cubic  foot  of  this  coal  would  weigh  82.76  flbs.;  according 
to  the  former,  only  81.58,  or  1.18  Ibs.  less.  This  shows  a  consider- 
able degree  of  porosity  of  the  coal ;  and  indicates  the  absurdity  of 
giving  the  weight  in  pounds  of  a  cubic  foot  of  coal  with  four 
decimals,  although  no  statement  in  regard  to  temperature  or  time  of 
weighing  is  made.  Such  accuracy  we  meet  with  in  some  of  the 
official  reports. 

F.   CALCULATION   OF   RESULTS. 

Referring  to  my  paper  in  No.  22  of  the  American  Journal  of 
Mining,  it  may  be  sufficient  here  to  state,  that  beside  the  per  centage 
composition  of  the  coal,  it  is  proper  to  reduce  the  composition  to  the 
combustible  =  100,  in  order  to  obtain  a  proper  comparative  estimate 
of -the  character  of  the  fuel  itself  (in  regard  to  the  proportion  of 
bitumen  and  carbon)  and  of  the  amount  and  quality  of  the  impurities 
ashes  and  moisture).  It  has  also  been  shown  in  the  paper  referred 
to,  that  for  considerable  areas  of  the  coal  -  field,  the  sum  of  the  con- 
stituents on  the  scale  of  combustible  =  100  is  the  proper  caloric 


268  REPORT  OF  STATE  GEOLOGIST. 

equivalent,  and  that  the  per  centage  of  the  combustible  in  the  fuel 
gives  a  proper  estimate  of  its  value. 

According  to  this  method  a  considerable  number  of  analyses  of 
Iowa  coals  have  already  been  made.  It  is  believed  that  the  results 
will  be  strictly  comparable  for  the  entire  coal  -  field  of  Iowa,  and  that 
the  conclusions,  both  practical  and  theoretical,  will  deserve  some 
confidence. 


THE  MINERALOGY  OF  IOWA, 


CHAPTER  IV. 

The  following  mineral  species  have  come  under  my  personal 
observation : 

ELEMENTS  :  1  Coal. 

2  Sulphur  (cryst). 
OXIDES  :  3  Quartz. 

4  Chalcedony. 

5  Hematite. 

6  Limonite  (and  Ochre). 
8  Wad. 

SULPHIDES  :  9  Galena. 

10  Blende. 

11  Pyrites. 

CARBONATES  :  12  Calcite  in  very  many  varieties  and 

forms. 

13  Smithsonite. 

14  Dolomite. 

15  Aragonite. 

16  Cerusite. 
SULPHATES,  anhydrous :     17  Celestine. 

18  Barytes,  hydrated. 

19  Gypsum. 

20  Epsomite. 

21  Alum. 

SILICATES  :  22  Kaolin  (and  fire  -  clay). 

By  reference  to  the  Report  on  the  Geological  Survey  of  Wiscon- 
sin, Volume  I,  1862,  where,  in  chapter  V,  Prof.  Whitney  gives  the 
mineralogy  of  the  lead  region,  we  may  consider  the  italicised  species 


270  REPORT  OF  STATE  GEOLOGIST. 

Sulphur,  Aragonits,  Carusite,  Celestino,  the  first  three  having  been 
(found  in  well  crystalized  specimens)  as  not  before  identified  in  Iowa. 
It  will  be  most  convenient  to  consider  the  minerals  of  the  princi- 
pal localities  separately. 

1.    THE  DUBUQUE  LEAD  REGION. 

1.  Galena. — Lead  sulphide,  PbS  ;  the  "mineral"  of  the  miners. 
This  ore  occurs  in  two  sets  of  lodes,  nearly  at  right  angles  to  each 
other.  The  principal  lodes  run  east  and  west,  the  secondary  lodes 
run  north  and  south ;  some  have  an  intermediate  course,  and  are 
called  quartering  lodes.  The  galena  from  these  lodes  may  be  readily 
distinguished. 

In  the  east  and  west  lodes  the  ore  is  usually  imbedded  in  the  clay, 
which  more  or  less  fills  the  cavity  produced  by  the  disintegration  of 
the  rock  (magnesian  limestone).  The  ore  itself  is  darker,  shows  fre- 
quently good  cubes  ("  dice  mineral "  of  the  miner),  has  a  good,  reg- 
ular, cubical  cleavage  throughout.  The  ore  is  sometimes  of  very  con- 
siderable dimensions. 

In  the  north -and  south  lodes  the  ore  occurs  usually  in  sheets, 
rarely  mors  than  three  inches  thick,  tightly  imbedded  in  the  rock. 
It  is  of  a  lighter  color,  never  shows  any  well  -  defined  cubes,  nor  any 
distinct,  regular  cleavage.  It  is  more  compact,  so  as  to  give  a  some- 
what ringing  sound  when  struck  ;  hence  it  is  also  called  "  steel  min- 
eral." It  is  said  to  yield  more  lead,  to  be  more  easily  reduced,  and 
to  contain  more  silver  than  the  east  and  west  mineral.  On  the  south 
fork  of  the  Little  Makoqueta  ri^er  much  of  the  north  and  south 
mineral  is  mined. 

In  the  quartering  lodes  the  characters  of  the  ore  are  also  inter- 
mediate. 

Crystaline  forms  observed  are  the  cube  and  the  octohedron ;  the 
latter  always  in  combination  with  the  former.  Very  fine  cabinet 
specimens  may  be  seen  in  the  cabinet  of  amateurs  and  miners  at 
Dubuque.  Some  specimens  have  cubes  only  on  one  side,  while  the 
other  is  studded  with  octohedra,  retaining  but  small  cubical  faces. 
The  largest  cube  I  have  observed  is  in  the  cabinet  of  Mr.  James 
Beach,  Dubuque;  it  measures  4JX4JX6J  inches,  has  the  corners 
unequally  replaced  by  octohedral  faces,  and  weighs  16J  pounds. 


REPORT  OF  STATE  GEOLOGIST. 


271 


2.  Blende.  —  Zinc  -  sulphide,   Zn   S;  the  "Black   Jack"  of  the 
miners.     It  is  not  as  abundant  as  the  former ;  more  common  on  the 
east  side  of  the  Mississippi.     Only  the  ferruginous,  black  variety  has 
been  observed ;  no  finely  -  developed  crystals,   although  the  masses 
exhibit  the  peculiar  dodecahedral  cleavage  very  well. 

The  disintegration  of  the  blende  takes  place  according  to  the 
directions  of  cleavage.  Several  specimens,  partly  disintegrated  to 
carbonate,  showed  this  feature  very  finely.  In  some  of  these  speci- 
mens of  carbonate,  the  dodecahedrai  rhombohedron  of  120  degrees  is 
easily  recognized. 

3.  Pyrites.  —  Iron  disulphide,  Fe  S2  ;  "mundic"  of  the  miners. 
Also  this  mineral  is  much  more  abundant  in  the  eastern  portion  of 
the  lead  region  of  the  Upper  Mississippi  than  in  the  Iowa  district  of 
this  region.     I  have  observed  it  in  most  beautiful  and  regular  octa- 
hedra  of  about  one  -  tenth  of  an  inch  ;  also  dodecahedra  have  been 
observed  by  me.     I  do  not  remember  to  have  seen  a  single  cube  of 
pyrites  from  this  region.     This  form  is  dominating  in  the  geodes 
in  southern  Iowa,  and  the  pyritohedron  I  have  seen  in  pyrites  from 
a  coal  -  mine  twelve  miles  south  of  Davenport. 

3.  Cerusite.  —  Lead  carbonate,  Pb03C.  The  galena  often  has  a 
white  coating  of  amorphaus  lead  carbonate.  In  the  quartering  lode 
of  Messrs.  Burton,  Hill  &  Co.,  I  found  some  very  good,  though  small, 
crystals  of  cerusite,  right  on  the  galena,  in  fissures  of  the  mineral. 

5.  Aragonite.  —  Prismatic,    calcium -carbonate,     Ca03C.        Mr. 
Woodman,  of   Dubuque,   has    obtained    some   very  fine  specimens, 
beautiful  groups  of  small  crystals,  from  a  cave  seven  miles  south 
of  Dubuque,  and  one  mile  west  of  the  river.     I  discovered  some, 
almost  microscopic  crystal,  right  on  the  galena,  in  fissures  of  the 
ore,  at  the  above  -mentioned  mine  of  Burton,  Hill  &  Co,  five  miles 
north  of  Dubuque. 

6.  Calcite.  —  Rhombohedral  calcium-carbonate,  Ca03C,  the  "  Tiff" 
of  the  miners.     It  is  very  common  in  the  diggings.     The  scaleno- 
hedron  R3  is  at  times  found  very  finely  developed,  in  combination 
with  the  vertical  hexagonal  prism  and  the  fundamental  rhombohedron; 
the  crystals  often  projecting  three  and  more  inches. 


272  REPORT  OF  STATE  GEOLOGIST. 

In  the  pools  of  the  caves  large  cakes,  consisting  of  an  aggloinera 
tion  of  acute  rhornbohedra  with  parallel   axes,  are  formed  by  slow 
crystalization.      The    surfaces    of    these    rhombohedra    are    never 
smooth,  being  studded  with  smaller  rhombohedra  of  the  same  form 
and  in  parallel  position. 

Rock  -  milk,  pure  white,  associated  with  Wad,  has  been  found  in 
specimens  from  the  Peacock  mine. 

Stalactites  and  Stalagmites  of  considerable  size  are  still  seen  in 
Dubuque ;  Satin,  Velvet  Spar,  forming  beautiful  arborescent  forms, 
may  be  seen  in  the  local  cabinets. 

The  most  remarkable  calcite  crystal  I  have  observed  is  a  scaleno- 
hedron  from  the  Peacock  mine.  It  is  about  three  inches  by  two,  and 
at  a  distance  of  f  inches  below  its  surface,  a  perfectly  parallel 
scalenohedron  is  finely  marked  by  very  small  crystals  of  pyrites. 

7.  SmitJisonite. — Zinc -carbonate,  Zn03C.     The    common    amor- 
phous  variety,   resulting    from  the  blende,  is    quite    frequent ;  the 
miners  call   it  "  dry  bone."     From   the  iron    of  the    black -jack  it 
is  always  yellowish  or  reddish. 

Very  finely  crystalized  Smithsonite  is  rare,  but  has  been  observed  ; 
some  crystals  were  fully  TV  inch  in  diameter. 

8.  Barytes.  —  Barium  -sulphate,    Ba04S    or  heavy    spar.     Good 
tabular  crystals  of  bluish  tint   have   been    observed,  from    Peacock 
mine. 

Gypsum. — Hydrated  calcium  -  sulphate,  Ca04S-f-2H20.  It  is 
not  common  in  the  lead -mines;  usually  in  small,  scaly  coatings, 
and  tabular  crystals ;  also  bunches  of  fibrous  gypsum  (Peacock 
mine.) 

10.  Sulphur,  S. — Beautiful  crystals,  about  J  inch  in  diameter, 
fine  yellow  color,  on  galena,  probably  from  the  St.  John's  diggings, 
four  to  five  miles  north  of  Dubuque.  Beside  the  terminal  plane 
(OP),  and  the  fundamental  pyramid  (P)  ;  also  JP  distinctly 
observed. 

"While  at  the  Hickock  mine  (July,  1867)  I  discovered  a  consider- 
able amount  of  solid  sulphur  and  dry  bone,  on  blende.  The  pieces 
•were  often  as  large  as  a  small  pea,  quite  compact,  exhibiting  some 
lustre,  but  no  distinct  crystalization.  The  shaft,  wherein  these 
specimens  were  obtained,  was  only  about  twenty  feet  deep. 


KEPORT  OP  STATE  GEOLOGIST,  273 

11. —  Wad,  impure  manganese-oxide.  Associated  with  rock -milk 
at  the  base  of  stalactites  from  the  Peacock  mine.  Also  found  at  the 
mine  of  Burton,  Hill  &  Co. 

12. — Limonite,  hydrated  ferric-oxide,  Fe203+3H20.  Impure,  not 
fine  specimens,  quite  common.  Yellow  ochre  rather  abundant. 
Goethit,  in  fine  scales,  doubtful. 

The  order  of  succession  of  these  minerals,  as  resulting  from  a 
careful  and  minute  study  of  all  the  specimens  of  the  survey  and  a 
great  many  most  excellent  specimens  in  the  cabinets  of  gentlemen  at 
Dubuque,  is  for  the  Dubuque  lead  region  essentially. 

ROCK  :  Galena  limestone  (a  dolomite). 

1.     Pyrites. 


4.  Limonite. 


2.   Galena. 


5,    Cerusite. 


3.    Blende. 


Smithsonite. 


7.  Sulphur.  Sulphur. 


8.  Calcite. 

9.  Gypsum. 

'    —-*** 10.  Barytes. 

Several  of  these  occur  more  than  once  in  the  series ;  in  the  above 
is  given  the  order  of  their  first  occurrence. 

On  the  east  side  of  the  river  the  order  of  the  sulphides  is  appa- 
rently the  reverse.  In  a  great  number  of  very  fine  specimens  from 
Galena,  Illinois,  and  from  Wisconsin  (some  of  which  I  studied  in  the 
cabinet  of  Mr.  Woodman,  of  Dubuque,  the  order  of  the  sulphides  is 
blende  —  galena  —  pyrites;  while  for  the  Iowa  lead -region  it  seems 
to  be,  pyrites — galena  —  blende.  It  must  be  stated,  though,  that 
the  specimens  from  Illinois  were  rather  finer  than  any  from  Iowa  I 
have  been  permitted  to  study. 

On  one  fine  specimen,  observed  on  board  a  Mississippi  steamboat, 
I  noticed  calcite  partly  between  galena  and  pyrites.  Part  of  the 
galena  was  coated  with  calcite,  and  over  the  remaining  galena  sur- 
face, and  part  of  the  caleite,  pyrites  had  been  deposited  in  octahedra 

and  dodecahedra. 
35 


274  REPORT  OF  STATE  GEOLOGIST. 

2.    THE  GEODE  REGION. 

For  the  location  and  extent  of  the  region  where  the  "  geode  bed  " 
occurs  in  Southern  Iowa,  we  refer  to  the  published  Geology  of  Iowa. 

A  great  number  of  geodes,  particularly  from  Bentonsport,  Van 
Buren  county,  have  been  closely  studied.  These  geodes  varied  from 
one  inch  to  one  foot  in  diameter;  many  were  quite  globular,  and 
many  are  flattened.  The  wall  varies  very  much  in  thickness,  and 
this  thickness  is  not  at  all  proportionate  to  the  dimensions  of  the 
geode.  The  outer  surface  is  always  uneven,  rough.  At  times  it 
contains  a  number  of  good,  more  or  less  corroded,  cubes  of  pyrites. 
No  other  minerals  have  been  noticed  on  the  outside  of  the  geodes. 

The  following  minerals  have  been  observed  on  the  inside  of  the 
geodes : 

1.  Chalcedony  forms  always  the  outer  crust,  often  more  than  an 
inch  thick.     Some  geodes  contain  no  other  mineral ;  then  the  chalced- 
dony  is  of  a  peculiar  mammellar  structure,  and  often  shows,  in  its 
fracture,   agate  -  like  bands.     Colors   are  usually  not  showy ;  pale 
gray,  bluish  -  gray,  and  yellowish  -  gray  predominate  ;    greenish  and 
reddish   tints   have    been .  observed.      Some   of  these    chalcedonic 
specimens  are  very  fine. 

2.  Quartz,  silicon  di*oxide,  Si02. — It  occurs  always    implanted 
on  the  chalcedony.     Nearest  the  latter  the  quartz  is  only  crystaline, 
but  farther  toward  the  interior  of  the  geode  the  structure  of  the  quartz 
becomes  more  regular,  and  the  inner  free  surface  is  always  formed 
of  fine  crystals.     Very  often  these  radiate  from  a  common  center, 
forming  bunches  in  various  parts  of  the  geode ;  the  center  is  always 
a  tube. 

The  most  common  crystaline  form  is  the  hexagonal  pyramid, 
implanted  on  the  inner  surface  of  the  geode ;  but  the  rhombohedran 
of  94°  is  also  quite  common,  often  very  large  (half  an  inch 
along  the  edges  !)  In  a  lot  of  geodes  from  Hamilton,  Illinois, 
collected  by  Mr.  Safford,  a  regular  gradation  from  this  rhombohedral 
quartz  to  the  peculiarly  rounded  chalcedony  could  be  traced,  pure 
quartz  rhombohedra  —  the  same  very  thinly  coated  with  chalcedony — 
this  coating  thicker,  so  the  edges  appear  quite  rounded ;  finally  the 
rounded  forms  of  chalcedony. 


REPORT  OF  STATE  GEOLOGIST.  275 

In  many  geodes  the  hexagonal  prism  is  very  finely  developed,  both 
in  combination  with  the  rhombohedron,  and  with  the  hexagonal 
pyramid  ;  in  many  this  pyramid  had  only  the  alternate  (rhombohedral) 
faces  well  developed,  the  others  being  often  rudimentary.  This, 
together  with  the  occurrence  of  the  rhombohedron  alone,  again  is  in 
favor  of  considering  the  rhombohedron  as  the  fundamental  form. 

Some  geodes  contain  a  great  number  of  loose  quartz  crystals,  up 
to  half  an  inch  in  length.  The  fine,  transparent  crystals  of  this 
kind  belong  to  the  most  evenly  -  developed,  and  most  beautiful 
rock  crystals  I  have  seen.  These  loose  crystals  have  always  a 
hexagonal  prism  of  some  length ;  and  in  some  geodes  this  is  com- 
bined with  the  rhombohedron  alone,  in  others  with  the  hexagonal 
pyramid,  usually  with  the  two  rhombohedral  halves  unequally 
developed-,  but  at  times  the  hexagonal  pyramid  is  also  perfect. 

In  a  few  geodes,  thick  short  quartz  crystals  (prism  and  pyramid) 
were  found  densely  studded  with  minute  pyramidal  quartz  crystals, 
so  as  to  form  rounded  bunches  of  exquisite  beauty. 

The  colors  of  quartz  in  these  geodes  is  various — from  clear 
transparent  to  white,  yellowish,  dark -yellow,  yellowish  -  brown,  red; 
some  few  have  a  fine  rose  color. 

3.  Calcite  occurs  quite  frequently,  often  filling  the  whole  cavity 
of  the  geode,  usually  resting  on  quartz.  Sometimes  the  crystals  are 
very  large  and  beautiful,  but  the  surfaces  have  a  somewhat  silky 
luster,  due  to  the  partial  disintegration  in  the  direction  of  the 
cleavages.  The  principal  forms  observed  are  : 

1.  The  fundamental  rhombohedron  of  105°  5'. 

2.  The  first  obtuse  rhombohedron  or  JR  of  135°.     In  one  geode 
from  Keokuk  several  of  these  occur,  one  having  a  diameter  of  three 
inches,  and  a  hight  of  one  inch. 

3.  The  veritical    hexagonal   prism;  the  longest  observed  is  3| 
inches  (1J  inch  diameter) ;  the  thickest,  2  J  inches  in  diameter  (and 
3  inches  long). 

4.  The  common  scalenohedron,  R3  of  104°  38'  and  144°  24'  in 
the  terminal   edges ;  only  subordinate  in  combinations  with  No.  3 
and  No.  6. 

5.  The  scalenohedron  f  R2,  having  the  terminal  edges  of  164° 


276  REPORT  OF  STATE  GEOLOGIST. 

and  130J°.     This  with  the  prism  of  2J  inches  diameter  and  3  inches 
height. 

6.  The  scalenohedron  JR5,  having  the  terminal  edges  of  146° 
and  128°;  in  another  geode,  in  combination  with  the  hexagonal 
prism  of  3J  inches  length  and  1J  inches  diameter. 

4.  Dolomite.  —  (Mg,Ca)   03C.     Yery  fine  varieties  of  pearl  spar 
have  been  observed  in  several  geodes.     Some  portions  had  been  con- 
verted into  limonite,  without  losing  the   characteristic  form.     The 
largest  crystals  of  this  kind  I  observed  in  a  geode  from  Hamilton, 
Illinois ;  the  edges  being  nearly   half  an  inch  long. 

5.  Pyrites  occur  quite  frequently  in  these  geodes  —  almost  always 
in  the  form  of  small,  very  regular  cubes.     Only  very  few  had  their 
corners  finely  truncated  (octahedral)."    The  largest  cubes  were  found 
on  the  outside  of  a  few  geodes. 

In  one  geode  a  mass  of  pyrites  (one  inch  by  one  and  one  -  half 
inches)  represents  on  its  surface  a  peculiar  foliaceous  structure.  The 
angless  do  not  correspond  with  selenite,  nor  do  they  quite  coincide 
with  rhombohedral  calcite ;  yet  the  mass  seems  to  be  a  pseudo- 
morph. 

The  pyrites  is  but  rarely  quite  unaltered  in  these  geodes  ;  it  occurs 
frequently  converted  into 

6.  Hematite,  Fe203,  and  also  into 

7.  Limonite,  retaining  the  form  perfectly  and  often  including  a 
small  nucleus  of  unaltered  pyrites  in  the  middle. 

8.  Ochre,  particularly  the  yellow,  fills  some  cavities  almost  en- 
tirely. 

9.  Blende  has  been  observed,  in  one  geode  as  much  as  half  an 
inch  cube.     Smithsonite  has  not  been  noticed  by  me. 

10.  Kaolin  or  porcelain  clay  is  found  as  a  fine,  perfectly  white 
powder  in  many  geodes. 

11.  Incrustations   of   various   colors   and  compositions    are  fre- 
quently coating  quartz,  calcite  and  others.    Calcareous  incrustations 
are  the  most  common,  and  as  far  as  observed  are  usually  local,  speak- 
ing for  infiltration. 

The  general  order  of  succession  of  these  minerals,  in  the  geodes 
observed  by  me,  is 
1 .     Chalcedony. 


REPORT  OF  STATE  GEOLOGIST.  277 

2.  Quartz  —  often  again  coated  by  chalcedony ;  and  again  on  this 
latter  beautiful  and  minute  quartz  crystals  have  heen  observed. 

3.  Pyrites  and  Blende,  the  former  often  converted  into  hematite, 
or  even  limonite. 

4.  Caleite  —  sometimes    intergrown   with  quartz,  also  in  a   few 
instances  coated  with  chalcedony. 

Dolomite  appears  to  succeed  the  calcite. 

5.  Incrustations  and  Kaolin.  —  In  a  few  cases  pyrites  has  been 
observed  right  in  the  chalcedony  of  the  outer  crust. 

A  few  acicular  crystals  were  observed  in  one  geode,  in  pure 
quartz.  These  crystals  look  precisely  as  fleches  d'amour,  or 
acicular  crystals  of  Rutile,  Ti02.  In  the  hope  of  getting  more 
material,  a  final  examination  has  been  delayed. 

FORT  DODGE,  WEBSTER  COUNTY. 

1.  Gypsum,  quite  abundant.      The   most  common   is   the  gray, 
massive  variety  ;  it  burns  white.     The  snow  -  white  gypsum  from  this 
region  is  nearly  chemically  pure,    and  shows  needles  of  gypsum- 
crystals. 

Separate  selenite  crystals,  not  very  regular,  but  of  the  common 
arrow  -  head  variety,  have  been  examined  from  the  same  county. 

2.  Celestine,     strontium    sulphate,     Sr04S. — Bluish     columnar; 
no  fine  crystallizations.     Columns  vertical ;  one  to  three  inches  iong, 
the  thickness  of  the  deposit. 

3.  Pyrites,  in  globular  masses. 

4.    WAVERLY,  BREMER  COUNTY. 

1.  Calcite,  very  clear,  finely  crystalized,  hexagonal  prism  with 
the  first  obtuse  rhombohedron  J  R  of  135°;  diameter  about  f  inch. 

Calcite  Geodes  from  this  place  show  a  fine,  almost  silky  lustre,  and 
the  rhombohedra  of  83°  (J  R)  and  of  124°  (f  R)  and  also  the  com- 
mon scalenohedron  (R  3)  together  with  the  vertical  prism. 

The  variety  of  Anthraconite  is  quite  abundant  at  this  place.  It  is 
very  fetid  when  struck,  has  a  fibrous  to  columnar,  at  times  radiated 
structure;  the  free  extremities  of  the  crystals  show  the  rhombohe- 
dron of  83°  (JR).  Associated  with  this  Anthraconite  is 


278  REPORT  OF  STATE  GEOLOGIST. 

Dogtooth  spar,  showing  the  common  scalenohedron  (ft  3),  some  pro- 
jecting fully  half  an  inch. 

With  the  first  -  mentioned  hexagonal  prisms  of  calcite  occurs. 

2.     BaryteS)  bluish  tables,  containing  small  crystals  of 


3.     Pyrites. 


5.    IOWA  FALLS,  HARDIN  COUNTY. 


1.  Colette,    Scalenohedra    (R3)    and    probably    also    ( —  2  R  3), 
terminated  by  the  obtuse  rhombohedron  JR.     Often  one  -  half  inch 
long. 

2.  Fire- Clay,  very  pure;  associated  with  a  pure  white  marly  clay. 
The  fire-clay  consists  of  pale -reddish  sand,  16  per  cent;  clay  84 

per  cent ;  containing  water  and  volatile  matters  34  per  cent. 

The  white  marly  clay  (much  more  plastic  than  the  former)  con- 
sists of : 

Alimuna 27.85 

Silica 26.66 

Water 13.28 

Giving  clay 69.79  per  cent. 

Lime 9.45 

Carbonic  acid 7.42 

Giving  calcium  -  carbonate %  16.87 

Hygroscopic  water 12.00 

Organic  matter  and  loss 1.34 


100.00 
6.    VARIOUS  LOCALITIES. 

Alum  from  Albia,  Monroe  county. 

Barytes  from  Elk  Creek,  Decatur  county. 

Barytes  from  Madison  county,  West  Line. 

Calcite  from  quarry  opposite  State  University,  at  Iowa  City,  west 
bank  of  Iowa  river.  Very  beautiful  fundamental  rhonibohedra  (^R), 
also  having  their  lateral  edges  bevelled  according  to  R3,  and  finally 
this  scalenohedron  alone.  In  some  specimens,  one  cavity  may  be 
filled  with  one  of  these  forms,  another  cavity,  an  inch  or  so  distant, 


REPORT  OF  STATE  GEOLOGIST.  279 

contains  the  other  form  exclusively.  The  largest  crystal,  about  two 
inches  long,  very  regular,  R8  and  R  combined. 

Dendrites,  from  Anamosa,  Jones  county,  on  slabs  ;  from  Dubuque, 
on  an  orthoceras. 

Upsomite,  or  epsom  salt,  efflorescent  incrustations  from  near  Bur- 
lington. 

Flint,  Madison  county. 

Hematite,  near  Keosauqua,  Van  Buren  county. 

Pyrites,  pyritohedra,  from  James'  coal- bank,  12  miles  below 
Davenport. 

Tuienmergel,  very  good  specimens,  from  Webster  county  and  from 
Page  county. 

Crystallites]  these  peculiar  concretiona  have  been  obtained  from 
near  Burlington  and  Iowa  City.  I  think  they  are  pseudomorphs 
after  gypsum  or  celestine. 


Page  173,  top  line,  for  "Surface  Geology"  read  "Geology." 

Page  85,  14th  line  from  the  top,  for  ''class"  read  "clays.\ 

Page  175,  12th  line  from  the  top,  for  "gronps"  read  "group." 

Page  178,  3th  line  from  the  top,  for  vlthen"  read  "there." 

Page  178,  10th  line  from  the  bottom,  '"groups"  read  "group." 

Page  179,  13th  line  irom  the  bottom,  for  "bands"  read  "band." 

Page  ISO,  15th  line  from  the  bottom,  for  "modules1'  read  "nodule*." 

Page  182,  6th  line  from  t hi;  top,  for  "This  band"  read  "Bolow  this  band." 

Page  183,  4th  line  from  the  bottom,  for  "the  conspicuous"  read  "the  most  conspicuous 

Page  11)1,  top  line,  for  "Geology"  read  "  Surface  Geology." 

Page  192,  12th  line  from  the  top,  for  "mark"  read  "reach." 

Page  1t»5,  I7th  line  from  the  bottom,  for  "if  no  other  than  this"  read  "if  for  no  other 

than  their  " 

Page  193.  17th  line  from  the  bottom,  for  '"visited"  read  "viewed." 
Page  197,  19th  line  from  the  bottom,  for  "depression"  read  "depressions." 
Page  198,  17th  line  from  the  bottom,  for  "Granite"  read  "Grant." 
Page  198,  14th  line  from  the  bottom,  for  "are  seen  only"  read  "are  best  seen." 
Page  li>9,  12th  line  from  the  top,  for  "rills"  read  "wells." 

Page  199,  17th  line  from  the  bottom,  for  '  the  influences"  read  "the  same  influence!." 
Page  199,  fith  line  from  the  bottom,  for  "various"  read  "forest." 
Page  1SH),  8th  line  from  the  bottom,  for  "interspersed"  read  "interrupted." 
Page  200,  15th  line  from  the  top,  coma  between  "horizon"  and  "like." 


GLOSSARY. 


The  law  authorizing  the  present  geological  survey  provides  that  a  glossary  shall 
accompany  each  volume  of  reports. 

Alluvial  —  That  which  is  deposited  by  the  washing  of  rivers  along  their  course. 

Amplexus  —  A  genus  of  fossil  corals. 

Anticlinal — A  given  line  or  ridge  from  which  the  strata  dip  in  both  directions. 

Arenaceous — Sandy,  containing  sand. 

Argillaceous  —  Clayey,  containing  clay. 

Aulosteges — A  genus  of  fossil  shells. 

Axophyllum  —  A  genus  of  fossil  corals. 

Black  -  haw  —  Viburnum  prunifolium. 

Slock- locust — Robinia  pseudo  •  acacia. 

Bluff -deposit — The  formation  composing  the  Missouri  river  bluffs.      See 

article  on  "  Lakes  of  Iowa,  past  and  present." 
Beyrichia  —  A  genus  of  minute  fossils  belonging  to  the  same  order  with  crabs 

and  lobsters. 
Borers  —  The  larvae  of  an  insect  that  deposits  its  eggs  upon  the  bark  of  the 

black-  locust.    When  the  larvae  are  hatched  they  bore  their 

way  into  the  body  of  the  tree  in  such  numbers  as  to  destroy  it; 
Bottom  —  A  Western  term,  applied  to  the  low,  flat,  alluvial  lands  so  common 

along  western  rivers. 
Coal-measures  —  A  name  for  that  assemblage  of  carboniferous  strata  which 

contains  the  coal. 

Conglomerate  —  Gravel  and  sand  consolidated  into  rock. 
Cottonwood  —  Populus  monilifera. 
Cranberry  —  common — Vaccinium  macrocarpum. 
Cranberry  —  high  -  busli  —  Viburnum  oxyccccus. 
Crania  —  A  genus  of  fossil  shells. 
Cretaceous  —  The  name  of  a  geological  age.    The  chalk  of  Europe  belongs 

to  the  cretaceous  age. 
Crustacean  —  Belonging  to  one  of  the  animal  sub  -  kingdoms.    It  embraces 

insects,  lobsters,  crabs,  star  -  fishes,  &c. 
Cryptacanthia  —  A  genus  of  fossil  shells. 
Cryptoceras  —  A  genus  of  fossil  shells. 
Cythere  —  A  genus  of  minute  fossils,  related  to  Beyrichia. 
Drift—  The  formation  which  contains  the  boulders. 
Drifting  —  Digging  a  way  horizontally  into,  or  within  a  mine. 
36 


282  GLOSSARY. 

Fauna  —  A  term  used  in  geology  to  signify  the  aggregate  of  all  the  animal 
remains. 

Ferruginous  —  Containing  iron. 

Fault  —  A  break  in  the  continuity  of  strata  by  the  lifting  or  settling  of  one 
part  of  them. 

Qeodes  —  Hollow,  concretionary,  stony  masses,  usually  lined  with  crystals. 

Grit  —  Coarse  sandstone. 

Habitat  —  The  naturally  chosen  place  of  habitation  or  growth  of  an  animal 
or  plant. 

Hydreionocrinus —  A  genus  of  fossils  belonging  to  the  same  order  with  star- 
fishes. 

Inoceramus —  A  genus  of  fossil  shells. 

In  situ  (latin)  —  In  place. 

Lacustrine  —  Formed  by,  or  belonging  to  a  lake. 

Marlite  —  Limy  clays,  usually  in  indistinct  layers;  common  among  the  coal- 
measure  strata. 

Meekella  —  A  genus  of  fossil  shells. 

Micaceous  —  Containing  mica. 

Nautilus  —  A  genus  of  shells,  both  fossil  and  recent. 

Protozoan  —  belonging  to  the  lowest  branch  of  the  animal  kingdom. 

Pinna  —  A  genus  of  fossil  shells. 

Shaft  —  A  perpendicular  way  into  a  mine. 

Sphagnum  —  A  genus  of  mosses,  several  species  of  which  usually  grow  pro- 
fusely upon  peat  -  marshes. 

Stratum  (plural,  strata)  —  layers,  or  beds  of  rocks. 

Synclinal — A  given  line  or  longitudinal  depression,  toward  which  the  strata 
dip  in  both  directions. 

Timber  —  A  term  applied  in  the  West  to  all  native  groves  or  bodies  of  forest- 
trees. 

Tomoceras  —  A  genus  of  fossil  shells. 


INDEX 


PAGE. 

Adams  county , 66 

Adair  county 68 

Anamosa  quarries 27 

Appanoose  county.  . . 40 

Black  Hawk  county 20 

Boonsboro,  coal  mines  ol  142 

Burlington  and  vicinity 30 

Cass  county 65 

Coal,  Chemist's  letters  on  205 

Coal,  proximate  analyses,  &c.,  of,  Prof.  Hinrichs  on 248 

Coal  -  field  of  Iowa 163 

Collections 167 

Davis  county 35 

Decatur  county 42 

Des  Moines,  coal  at  city  of 167 

Drift  phenomena  in  southwestern  Iowa _ 143 

Fort  Dodge,  coal,  stone,  &c.,  at 140 

Fort  Dodge,  gypsum  at 135 

Franklin  county 119 

Fremont  county 50 

Fuel,  Chemist's  letter  on 205 

Geology  of  Raccoon  river  region,  O.  H.  St.  John  on 173 

Gypsum  at  Fort  Dodge 135 

Hamilton  county 25 

Hardin  county 21 

Hinrichs,  Prof.  G.,  first  report  of. 9 

Hinrichs,  Prof.  G.,  second  report  of 204 

Hinrichs,  Prof.  G.,  letters  of. 205 

Indian  mounds.  148 

Introductory 13 

Jefferson  county 94 

Jones  county 27 


284  INDEX. 

PAGE. 

Lakes  of  Iowa 151 

Lead  mines  of  Dubuque 97 

List  of  fossils 168 

Madison  county r . .  70 

Mahaska  county , 91 

Marion  county 100 

Marshall  county 117 

Mills  county 56 

Mineralogy  of  Iowa,  Chemist's  report  on 264 

Monroe  county. 93 

Montgomery  county 63 

Page  county 47 

Peat 121 

Petroleum 36 

Pottawattamie  county , . .     59 

Ringgold  county 43 

Rocks,  Chemist's  letter  on 238 

Salt 74 

Soil,  vegetation,  &c . . .  165 

St.  John,  O.  H.,  Report  of 84 

St.  John,  O.  H.,  Letters  of. 173 

Surface  geology  of  middle  region  of  Western  Iowa,  O.  H.  St.  John  on 172 

Taylor  county 45 

Union  county 69 

Van  Buren  county 112 

Walled  Lakes 151 

Wapello  county 108 

Waters,  Chemist's  letters  on 233 

Wayne  county , .   .  40 

Webster  county 26 

White,  Dr.  C.  A.,  First  Annual  Report  of. 5 

White,  Dr.  C.  A.,  Second  Annual  Report  of 81 

White,  Dr.  C.  A.,  Letters  of  for  1866.  20 

White,  Dr.  C.  A.,  Letters  of  for  1867 91 


_ 


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